Wednesday, August 16, 2017

Describing Gems in Millimeters: Some Comparisons to Help

When buying gems or jewelry online, it's hard to know what "8mm" means in terms of size.  You can look at a ruler and on the opposite edge of Inches are CM (centimeters) and MM (millimeters).  Inches have lines for each 1/8 of an inch and 1/16 of an inch.  On the centimeter side, there are 10mm to one cm, and about 25mm to one inch.  But that's still hard to judge the size of a gemstone. Chain widths are also measured in millimeters, so it can be surprising to see how tiny a chain will look in person. Chains can be as small as under 1mm (.8 or even smaller).  Nylon or silk cords can be less than .5mm---like a thread.

Rulers have inches on one edge, mm on the other


Sellers take very close pictures of the jewelry they're selling and buyers can be disappointed at how tiny gems actually are, even with measurements listed.
1-ct diamond ring = 6.5mm diameter



So I put together a quick chart to help judge sizes, comparing millimeters to everyday objects and the approximate carats of round-cut diamonds:


                         SIZE              DIAMETER
      • 1mm          Grain of sugar      
      • 1.25mm     1-point round diamond
      • 4mm          .25-ct. diamond, match head
      • 5mm          Pea, and .50-ct. diamond
      • 6mm          Pencil eraser 
      • 6.5mm       1-carat round diamond
      • 8mm          2-carat round diamond 
      • 9.25mm     3-carat round diamond
      • 10mm        Standard thumbtack head
      • 11mm        AAA battery, and 5-ct. diamond
      • 14mm        AA battery
      • 16mm        Button on a pair of jeans
      • 17mm        A battery
      • 18mm        Dime
      • 19mm        Penny
      • 21mm        Nickel
      • 24mm        Quarter 

      •  3mm  = 1/8"
      •  6mm  = 1/4"
      •  8mm  = 5/16"
      • 10mm = 3/8"
      • 13mm = 1/2"
      • 19mm = 3/4"
      • 23mm = 7/8"
      • 20mm = 1"
 I hope this helps you "see" the sizes of gemstones so you know exactly what you're buying!


Sunday, July 23, 2017

Do Gemstones Break? Can a Diamond Break? Info About Gem Hardness

If you hit a diamond with a hammer, it’ll shatter into a dozen pieces. If you hit a piece of quartz with a hammer, it’ll split in two. If you hit a piece of jade with a hammer, it’ll ring like a bell!


That's an old jeweler's saying.   We all know that diamonds are the hardest gemstones.  So can a genuine diamond really shatter?  What if it's dropped onto the floor?  What about other gemstones?


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I read in the Amazon forums that a buyer felt that their gemstone necklace was "fake" because the stone broke when she dropped it onto her tile floor!   She felt that only something that was glass would break from dropping it onto a hard floor.  She expected a refund, and the jewelry seller sought advice from other Amazon sellers, most of whom aren't jewelers.  Some of the responses were in favor of the buyer (they "didn't know if genuine gems would ever break"), and others in favor of the seller.  So I thought I'd write about gemstones, their hardness, and their wearability.
==============================

OVERALL DURABILITY OF GEMS

The "hardness" of a gem is only one factor in determining a gemstone's durability.  Gemologists take into consideration other factors:  ability to withstand heat, light, chemical exposure (household cleaners etc.), and humidity, stone treatments, gem cleavage, and even the cut of a gem.  So gemstones are evaluated by (1) hardness; (2) toughness; and (3) stability. All of these factors should be weighed when deciding which gemstone is right for you.

WHAT IS GEMSTONE HARDNESS?

This is a really misunderstood and confusing term.  In gemology, the word "hardness" has a different meaning---it simply means the ability to resist scratches and abrasions, and nothing more!  So really the hardness of a gem is measured by its "scratchability".

In the early 1900s, Freidrich Mohs developed a scale from 1-10 to describe minerals' ability to be scratched, with 1 being the softest and 10 the hardest.  This is known as the Mohs Scale of Hardness.  All gems are rated between 1-10 but the Mohs scale uses the following gems as an example:



Quartz Geode
Glass is about 5.5 on the Mohs scale so anything harder can scratch glass (not just a diamond!) including a CZ or quartz.  Only a diamond can scratch itself and all other gemstones.  The most important number on this scale is 7--quartz.  Why? Because quartz is the most common mineral on earth, and tiny flecks of quartz are constantly airborne (all the little specks of "dust" in the air are mostly quartz particles!) and so any gem with a lower Mohs grade than 7 will be easily scratched just by dust!   This is why it's advisable to rinse your jewelry off under water before rubbing it with a cloth--to avoid scratching it.

Each one of these minerals can scratch the one below it, and can be scratched by the one above it.    And the scale isn't linear, but is relative----Corundum (9) is twice as hard as topaz (8), and diamond (10) is four times as hard as corundum.  And with the mineral Kyanite, the hardness can vary within one crystal from 4 to 7.5!

There are also many minerals that are rated halfway between numbers, such as tourmaline which can range from 7.0 to 7.5.

GEMSTONE TOUGHNESS

This is the ability of a gem to resist breaking and chipping. 

Nephrite Jade--VERY Tough!
There is a Gemstone Fracture Toughness  Scale that measures the work required to separate a gemstone along a cleavage plane.   Values run from 600 (corundum) to 225,000 for nephrite jade.  Diamonds are rated at about 5,000-8,000.   A diamond is the hardest gemstone on the Mohs scale, but is also brittle.  The steel of a hammer won't scratch the diamond, but hitting it with the hammer will shatter it.  Daily wear of a diamond, with all the things the diamond will rub against and clunk against, over time will scratch the stone.  "Wearability" (also referred to as "toughness" or "durability") is the degree in which a gem will show wear.   Gems with a hardness of 6 (such as Opal) will quickly loose their polish due to tiny scratches over time.

Gems softer than Quartz (7) will lose their polish just from simply cleaning it over time.  Gems with a Mohs rating of 7 and up are considered very wearable a suitable for everyday wear.  Wearability is graded as Excellent, Very Good, Good, and Poor. Opals have a "Poor" wearability rating, which means it should be saved for special occasions or set in protective settings.
Opals--3% to 21% Water!

So.....a gemstone's "durability" is a function of its resistance to scratches (hardness) + resistance to breakage (toughness) + other special properties such as cleavage planes (or in the case of jade that "rings like a bell" mentioned at the top---an interlocking structure that makes it very tough.)   Certain gemstone cuts, like marquise, are more prone to chipping, as are gems that are loose in their settings.

GEMSTONE STABILITY

Just because a gem is hard doesn't always mean its wearability is "excellent."  Some gems are sensitive to chemicals, temperature changes, or even sweat!

Diamond cracked by thermal shock
Diamonds are very stable, but can also break when exposed to extreme temperature changes. "Thermal shock" is the term that describes the damage that can occur from extreme temp changes.

Some gems are vulnerable to humidity changes.  Opals can lose their moisture in dry conditions and crack.  Some gems can absorb water---malachite, amber and azurite.

Citrine, Amethyst, Prasiolite
Some gemstones can change or lose their color when exposed to light---amethyst, citrine, prasiolite, kunzite and topaz can fade when exposed to prolonged sunlight.  Organic gems can be ruined if exposed to prolonged light and heat---amber, coral, pearls, jet, and ivory.  Enamel can also be ruined when exposed to heat.

Chlorine and perfumes and makeup are chemicals that can also damage or discolor some gems, such as pearls.  Chlorine can also damage gold mountings!   Ammonia will damage the shine on turquoise, malachite, and coral.  Turquoise can easily absorb all sorts of oils and chemicals.

GEMSTONE TREATMENTS

Fracture-Filled Emerald
Some gems are coated. Some are facture-filled which can be damaged from heat and exposure to heat or solvents, like alcohol, or damaged from ultrasonic cleaning.






CONCLUSION

Gemstone hardness alone isn't a measure of a gem's toughness or wearability.  There are many other factors to determine how well a particular gem will wear over time.

So regarding that woman's assertion that "only a fake gem would break"--- she is WRONG.  Any gemstone can break when dropped onto a hard surface like a tile floor, including a diamond.   Some manmade stones, such as the Cubic Zirconia with a Mohs hardness of 8 or 8.5 or Moissanite with a Mohs hardness of 9.25, will resist scratches and chips better than most other gemstones.

Most gemologists or great websites such as the GIA will list each gemstone's Mohs rating, plus wearability grades.

It's important to always treat your gemstone jewelry with care---don't drop it, bump it, or wear while swimming or doing housework or working around chemicals.  Keep jewelry clean and safe while not wearing it.  Keep your jewelry in a jewelry box, away from other pieces of jewelry so they don't bump each other. Make sure any prongs are secure and stones aren't loose.  This will ensure that your fine jewelry will remain beautiful and last for generations.



Monday, July 17, 2017

"Opalite" Opal Simulant, Kyocera "Opals"---Not Really Opals


Someone read my blog post about the glass "opalite" that I've written about HERE.   They commented about a synthetic (created) Opal that is sold as opalite, and how it wasn't glass.  I responded, but I thought I'd write a little about it here also.

Back in the 1970s or early '80s, a Japanese company was manufacturing a plastic simulated opal and called it "opalite".  They had claimed it was a cultured opal, or lab-grown opal.  In the jewelry world, the word "synthetic" doesn't mean "fake"---it means a gemstone that is cultured that has the SAME chemical, physical and optical properties as its natural counterpart.  This would mean that a synthetic gemstone (such as synthetic ruby or sapphire, for example) is IDENTICAL to a mined gem, but would be flawless.

Plastic Opalite from GIA (1989)
In the 1980s, the GIA (Gemological Institute of America) did some tests on this "opalite" Opal product.  It was found to be PLASTIC, not an opal, and was identical to a lot of other simulated opal products found. 





Per the GIA: 
"A plastic imitation opal that shows true play-of-color was advertised as "new" and offered for sale under the trade name "Opalite" at the Gem and Lapidary Dealers Association (GLDA) Tucson show in February 1988. Subsequent gemological testing proved that this material was virtually identical to the plastic imitation opal previously described in the literature that was known to be manufactured in Japan. It is now being marketed worldwide under a new name"

HERE is a link to the pdf file from 1989 that is interesting to read, and has all the findings.

===================
Tested by GIA--NOT synthetic
Now, a Japanese company is manufacturing a Kyocera "opal" that is also NOT a true synthetic opal.  It is manufactured in blocks. It does NOT have the same chemical and physical properties of a genuine Opal and is therefore not a synthetic or cultured opal----it is a simulated opal.  A "simulated" gem (in this case Opal) is just something that is made to LOOK LIKE a gemstone---it's not a synthetic, which is grown and IS a gem, although manmade. 
Blocks of *simulated* opal --- not genuine Opal

HERE is a very interesting article from the GIA regarding Kyocera opals---no longer marketed as "opalite" by the way.  The conclusion in those findings is that the Kyocera opals are just simulants, not synthetics.  In other words, they are NOT opals.

While looking at images of Kyocera simulated opals, I found that there is a jewelry designer that is selling this simulated opal as "Kyocera opal" set in base metals (plated brass) for premium prices.  Buyer beware---a higher price tag gives the illusion of quality (basic Marketing 101) but doesn't mean it's genuine.    Here are some examples of the colors of SIMULATED (not real!) opals used:

None of these are opals---all are Kyocera SIMULATED Opals
This is considered "fashion jewelry" or "costume jewelry", not fine jewelry which incorporates genuine gems set in precious metals (gold, silver, plastinum). 

OPALITE GLASS


Opalite Glass--NOT a gem
In the early 1990s or around the time that this particular "opalite" opal was tested and confirmed to be just plastic, manufacturers in Hong Kong began making an iridescent glass that was known as "opalite glass".  Sellers seem to have forgotten the word "glass" in describing this material now, which is why I've written about it several times.  Current "Opalite" products sold are IRIDESCENT GLASS, and nothing more. 

Opalite has an iridescent glow that changes color when held against a dark or a light background.  It's more blue against darker colors, and more golden or pink against light colors.
Opalite--note the color changes

Another blogger concludes that this isn't even glass, but is plastic with cellophane inside!  Perhaps that's true, and some are plastic, but the ones I've seen in person have been glass.  Either way---NOT a gem!

The same designer I mentioned above who sells simulated Kyocera opals, is also selling Opalite.  Here's a great example of how colorless this glass (plastic?) is against a light background:

Opalite (glass) earrings---not gems











Saturday, May 27, 2017

Opalite IS Simply Glass (Not a Gemstone) and is NOT "Opal Glass," and Comments I Receive via Blogger

OPALITE
Opalite Glass
Today I've heard a couple of times (via the blogger "contact" form) from someone responding to my "Opalite is Just Glass and Not a Gemstone" post, who insists that Opalite "isn't just glass" because it's made with minerals which give it a glow.  I'm not going to publish the comments and I can't respond to their email (since their settings are set to "noreply-comment@blogger.com" as their email, it goes back to me!), so I'm going to respond right here in this separate post.  Hopefully this is a little bit informative for this person, and for anyone who might read this and wonder, "If glass is made from minerals, why isn't it a gemstone?"  But basically, this person today has confused Opalite (which is a man-made glass made in China for the jewelry industry as a simulated Opal or Moonstone) with "Opal Glass" which is a "thermally opalizable glass" used in manufacturing (jars, etc.) and who referred me to this patent from 1970.
This patent information is about Opal Glass---used in things like Corningware and cosmetics jars.  This has NOTHING to do with Opalite, used in jewelry.  I can see how this could be confusing, especially when unscrupulous sellers try to hawk this opalite glass as "opal glass" or "opal moonstone" and other misnomers.  I assume this person googled "opal glass" and found their way to my blog as well as that patent info.  So since this is confusing for some people, here is a little more VERY basic info about glass in general, and Opal Glass in particular: 

First: WHAT IS GLASS?
Ancient Roman Glass--Clear when Made

Glass (man-made) is made from melting minerals together at a very high temperature.  These minerals are silica (silicon dioxide), limestone (calcium carbonate), and soda ash (sodium carbonate), melted at 1700 degrees C. Glass is amorphic---meaning it has no crystalline structure.  The chemical structure of glass is SiO2  There are many other types of glass such as "crystal" or leaded glass (which adds lead oxide),  borosilicate glass which is made with boron trioxide which makes it very sturdy and is used as test tubes and sold as Pyrex for baking, for example, "Vaseline glass", plus many other types of art glass and so forth.

HOW IS COLORED GLASS MADE?
There are 3 different ways to make colored glass. Adding different minerals/metal salts to the basic glass recipe results in colors of glass.  Iron or Chromium is added for green glass; Cobalt for blue glass; Gold, Copper and Tin may be added to make red glass; and so forth.  HERE is a great website that explains this in detail along with a great chart at the top of the page.  Some glass is colored by suspended particles (colloidal) of minerals in the glass.  "Goldstone" and "Blue Goldstone" are great examples of glass with suspended minerals.

HOW ABOUT "MILK GLASS"?
Vintage "Opal" or Milk Glass Steins

This is a type of art glass made in the 19th Century and was known as "Opal Glass", then later called "Milk Glass".  It is a milky white opaque to translucent glass, but can also be found in assorted colors, formed in vases and cups and decorative objects.  It was made with different recipes---sometimes using a little arsenic, sometimes tin oxide, and usually fluorite.  This means that this glass will become fluorescent under a black light.  It's a collectible vintage glass now.

WHAT ABOUT THIS PATENTED "OPAL GLASS"?
There is a patented method of making "opal glass" from 1972 that describes how "opalescent glass" is manufactured for "thermally opalizable glass".  This is glass used in oven ware (low expansion, heat-resistant).  As it says in the patent info, opal glasses are "widely used in the fields of science, industry and commerce in the form of containers for...cosmetic creams, deodorant containers, lighting globes..." etc. The patent goes on to describe the chemistry of this oven-safe glass.

This has absolutely NOTHING to do with Opalite--a glass made in China specifically for the jewelry industry.
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 Knowledge of basic science will tell you that everything that is not growing or living (such as plants, animals) is a mineral, or made from minerals. "If it can't be grown, it must be mined."  Even living things (including people) are made of minerals.
===================================

The most-read post in my blog has been regarding Opalite glass.  This is a man-made glass and is often sold to consumers as a gemstone, with sellers calling it "Sea Opal" and "Opal Moonstone" and even just "Moonstone" when in fact it is NOT a gem, but is simply glass!  Glass which has no crystal structure, despite being made from minerals, is simply GLASS and therefore not a gemstone.  "Fused Glass" is often sold as Quartz when in fact it is also just glass (which I've written about several times as well).  I wrote about Opalite glass more than once, and have posted pictures of Opalite glass and Moonstones and Rainbow Moonstones, and have answered literally hundreds of questions about this Opalite-as-gemstone scam.  And it IS a scam when someone claims it is a "gemstone"!  I get a lot of questions asking if something is a real gemstone (and I enjoy getting questions and always try to help).  Sometimes I'll hear from someone who is trying to correct me on something---that's great!  I've updated many of my posts when I get solid information to add.  I'm here to learn too!

Anyway, whoever "Me" is who wrote to me regarding this patent and argued that "opalite" isn't "just" glass because it's made with minerals----thank you for taking the time to send me emails.  I hope you find this information helpful and informative. If  you have further questions regarding glass in general or Opalite glass in particular, please provide your email address so I can respond. 

Saturday, March 18, 2017

"Andara Crystal" - SCAM Alert

There are no more "mystical" properties in a chunk of this "Andara Crystal" glass than in a vase on your table, or your car's windshield, your wine glass, or a piece of a broken beer bottle.

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"Bag O'Glass" for $98 sold as Andaran Crystals
This is really sad to read---so many gullible people are being taken advantage of, so I feel compelled to write this.  BEWARE OF "ANDARA CRYSTAL"!

I wrote about pieces of glass being sold as "Obsidian" a few months ago.  Obsidian is natural Volcanic Glass and the colors of natural Obsidian are black, brown, grey, mohogany brown, spotted, and "sheen" varieties.  You can see my blog post HERE.  People are selling chunks of regular man-made glass as "obsidian"----in colors such as red, blue, purple, yellow, green----which aren't colors of actual Obsidian. 

Someone read my Obsidian post and wrote a note to me regarding a very big scam going around involving something being marketed as "Andara Crystal."  My search on Etsy showed 462 results.  My search on Ebay showed 449 results.  The first result on Etsy shows a wire wrapped piece of blue broken glass (an "Andara Crystal") nonsensically described as "... a conduit of the pure 'Blue Ray,'...emanating from the core of the universe, it's [sic] vibration is the holographic stream of the now, limitless as we are" which is on hold for someone---for $198!  RIDICULOUS, weird, and very sad that someone is charging nearly $200 for a wire wrapped piece of regular broken glass--and someone bought it!

WHAT ARE THE CLAIMS ABOUT "ANDARA CRYSTAL"?

Piece of broken glass for about $450!
There are SO many different descriptions of this "Andara Crystal", most of which are completely absurd and poorly written nonsense!  One website claims that the "gifts" brought by "Andara Crystals include:expanding awareness, universal knowledge, channeling ability, spiritual development, bridging ethereal and physical dimensions, raising energy frequencies, clearing the heart chakra," and many more.  And of course this website is selling different colors of "Andara Crystal" glass pieces, and each color possesses different properties!

Another website tells their "story of Andara Crystals" (emphasis mine):

"The Andara crystal is a very special gift from God that holds the energy of unconditional love ... is very rare ... comes from Native American Indian land... I knew there was something magical about this stone the first time I experienced it. I was given the message to have it cut into the sacred geometric shape of the earth. This is known as Metatron’s Cube*..."
*This chunk of glass was cut like a regular 6-sided cube.  Metatron's Cube is actually a dodecahedron seen HERE. I honestly thought they meant "Megatron" when I first read it--makes more sense! LOL!

3" shard of broken glass, $85
Another website tells you how to separate "fake Andara Crystals" from "genuine" ones! Again, emphasis is mine:

"The Andaras ... exist in only in two places; one is in the Sierras on Nellie's property*, the other is in a small sector in South Africa, which are not available as of yet because they are on a high profile diamond mine property with very high security.**
What distinguishes true Andaras from obsidian imitations is that there is always Etherium (prima Matra) present in genuine Andara Crystals. Etherium*** is a very rare combination of over 70 minerals ... The only available source of Etherium in the world is found on Nellie's land where the Andaras are present... True Andaras work with your DNA..."
 *I assumed that this seller lives on "Nellie's land" in the Sierras. But another site states: "Nellie, a half-Choctaw Indian, Medicine Woman and Shaman..." (Never mind that the Choctaw Nation is nowhere near the Sierras.)
**If it's a high-security diamond mine in South Africa, how does this person even KNOW that these "cystals" exist there?  
***Etherium is a completely made-up term.

Lilac "Monatomic" -- NO, it's glass
A TINY 1.5" x 2" piece of lavender or lilac colored glass (sold for about $95!)  is pictured left, and described as follows:
"Andara crystal is a glass-like transmuted mineral complex from this naturally occurring mineral deposit high in monatomic minerals. This natural glass-like mineral complex exhibits extraordinary metaphysical properties."
This is NOT glass-like or a mineral---it is 100% GLASS.  Also, "monatomic" is defined as: "elements that are present in the gaseous state as single atoms. These elements are the noble gasses: He, Ne, Ar, Kr, Xe and Rn."  Per a chemistry dictionary.

There are more websites that talk about "third hole dimensions" and "Alpha and Omega ancient days" and a "black hole frozen in space-time" and that these crystals are created where "a hyperfield forms a 'no-time' zone, where linear laws of thermodynamics are warped..." and other incredibly ludicrous and inane descriptions of this "Andara Crystal" and its "magical" properties. Word salad!!
$418 for this chunk of broken glass

WHAT ACTUALLY IS ANDARA CRYSTAL?

Shard of clear broken glass
Very simple:  it's a chunk of GLASS.  Man-made glass.  Just plain old everyday GLASS.  As one person on Mindat.org says: "As an experienced glassblower, I can tell you its just cullet glass."  Cullet glass is furnace-ready recycled glass.  There are no crystal structures at all in glass!  No minerals in glass!  There are no more "mystical" properties in a chunk of this "Andara" glass than in a vase on your table, or your car's windshield, your wine glass, or a piece of a broken beer bottle.  Slag is a type of glass that is left over from manufacturing processes---and is being sold as "Andara Crystal" in various colors.  Also, big hunks of broken glass are being sold on Ebay and Etsy for PREMIUM prices because the sellers are claiming this plain ol' glass possesses mystical and magical properties.

If you go to ebay or to etsy and search "Andara crystal" you will see pages and pages of broken shards of glass being sold for LOTS of money by unscrupulous sellers preying on vulnerable buyers. Or click HERE for a google image search of broken glass shards, being shilled as "Andara Crystals". 

HERE is a discussion of this scam on mindat.org, which is a reputable mineralogy website.

This is a very sad case of sellers taking advantage of vulnerable people!!

PLEASE----this is a total SCAM.  Buyers PLEASE beware!!

Saturday, March 4, 2017

"Silverite" Update---Is It Sillimanite? One Seller Says So!

White "Silverite" - Sillimanite?
I have written about a gemstone that is almost exclusively sold on Etsy, called "Silverite".  Sellers in India say it's a natural gemstone, and until now, that's all they would say.  I asked some wholesalers about "Silverite" and never got a really straight answer, other than to tell me what it's NOT----I heard it's "definitely NOT sapphire" and "definitely NOT coated".  Yet jewelry designers on Etsy (and elsewhere online) have described it as "coated sapphire", "opalescent quartz", and just a lot of other descriptions that they must have made up, since the actual wholesalers state otherwise.

Anyway, I bought some of this silverite over the past year and had it tested, and every piece that I had tested (from different sellers) turned out to be just glass.  One strand of silverite that I had tested was "coated glass", with some sort of mystic coating on it.

Silverite - Could Be Sillimanite
Tonight I heard from someone who pointed me to a new seller on Etsy who has Silverite.  This person told me that silverite is actually a trade name for "Sillimanite", which is a natural gemstone.  I looked at the listings, and YES, this seller states in the description that this is actually "natural Sillimanite".  HERE is a link to one of their listings.  As of March of 2017, the term "silverite" is not a registered trade name, and no gemologists have even heard of it (except for the ones I contacted about it---they heard of it from me) and it's not written about anywhere--not on mineral websites, the GIA, gemstone forums, nowhere.  The term "silverite" was registered at one point for a coating method, but it's a "dead" trademark and it had nothing to do with a gemstone name anyway. 

I haven't bought any of this new seller's silverite yet, and so I haven't had it tested, so I can't say for sure that this is a natural gemstone.  However, it's interesting to see a wholesaler offering silverite and describing it as Sillimanite.

I hope this is the case!  This seller seems reputable and has other nice gemstones, so hopefully this actually IS a gemstone (Sillimanite)!

Sillimanite is a gem that is closely related to Kyanite and Andalusite.  It's a hard gemstone, and a large amount of Sillimanite has been recently mined in India.  It's considered a collector's gem, and can be quite expensive.  Sometimes, sillimanite is dyed to look like precious rubies, emeralds and sapphires.  HERE is some good info regarding sillimanite.

And once again----no matter what "silverite" is, it is definitely NOT a sapphire, or corrundum; it is not a coated quartz; it is not a pearlescent coated opal, or any other type of precious gemstone.

If I get some of this Silverite, I will test it and let you know!

Friday, February 17, 2017

Moonstone v. Rainbow Moonstone---Same or Different Gemstone?

Moonstone
Moonstone is a very popular gemstone.  Rainbow Moonstone is also extremely popular, but are they the same gem?  How are they different?  Is Rainbow Moonstone just a variety of Moonstone? What about other colors of Moonstone, like peach, pink, or grey?   It's very confusing, even for jewelers and mineral collectors. Here's some information I've gathered about these gemstones---I hope this is helpful!



MOONSTONE
The minerals of the Feldspar group are the most widespread minerals around the world and make up 60% of the earth's crust. Basically, long story short, feldspars are a beautiful and complex gem family that includes Moonstone, Labradorite, Sunstone, Sanidine, and others. Moonstone is a variety of the feldspar group mineral orthoclase and is actually made of two minerals, orthoclase and albite. During formation, orthoclase and albite separate into two stacked, alternating layers. When light falls between these thin layers, it is scattered into many directions, producing the phenomenon called "adularescence." Adularescence is the light that appears to move across a gem, giving it a glowing appearance.  This glowing light moves as you move the gem.   This glowing feature can be a bright or subtle blue (deep or pale), white, grey, or even a "catseye" appearance:


Moonstone with "Catseye"


Moonstones are found in an array of colors---peach, orange, yellow, green, grey, black, blue---some with a white adularescence (like the moon) or with blue adularescence (like moonlight on water). Here is a screenshot of a chart showing the different colors of Moonstone---please visit HERE to see the original chart, and the pictures of each gem can be enlarged, plus more information on Moonstone:



As the chart shows, there's a wide array of each of the colors of orthoclase Moonstone.  Here is another example of some of the colors of moonstones which exhibit a very slight glow that to me looks a little like mother-of-pearl:
Colors of Moonstone

Other feldspar minerals can also show adularescence, especially Labradorite, which is found in Labrador, Canada.  Another form of Labradorite that is found in Madagascar is called Rainbow Moonstone.

RAINBOW MOONSTONE
Rainbow Moonstones
This gem has a multicolored adularescence over a light or transparent body color.  It can also have a singular deep blue adularescence.    It’s known with the trade name "Rrainbow Moonstone", despite the fact that it’s actually a variety of labradorite rather than orthoclase.  So a "Rainbow Moonstone" feldspar gem is closely related to Moonstone which is also a feldspar gem, but is of a different species of Feldspar.  Some Rainbow Moonstones look identical to a Moonstone and would need to be tested to tell the difference:
Rainbow Moonstone



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However, per the GIA:   "To be called moonstone, a mineral’s actual identity is not as important as the beauty of its adularescence."
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METAPHYSICAL PROPERTIES
Many people enjoy wearing gemstones for their metaphysical properties, or the lore behind the gem.  I'm a believer of the power of the mind!  Here are some beliefs regarding the powers of these gemstones:

MOONSTONE: a stone of intuition and insight; helps balance emotions and relieves stress and increases patience; attracts good luck and good fortune; allows one to see into the future. Ancient cultures believed that if you hold a moonstone in your mouth during a full moon, you can see into the future.

RAINBOW MOONSTONE: a magical stone with powerful protective properties and deflects negativity; helps its wearer find their true path in life; a stone of intuition and insight; balances emotions and increases patience; increases creativity; clears the mind and senses to allow for calm sleep; helps bring out psychic abilities.

SUMMARY
Moonstones and Rainbow Moonstones are closely related gemstones, but are not identical.  The information I trust the most and included here comes from the Gemological Institute of America.   Different information can be found on other websites, including Mindat.org, which has the world's largest database of mineral information and is updated daily.  On the Mindat website, there is information about exactly what IS a Moonstone, since the term "moonstone" is a generic term.  Even the discussions in the forums, with gem experts, find the classification of "moonstone" and "rainbow moonstone" to be confusing!

So, technically, a Rainbow Moonstone is really a transparent Labradorite feldspar mineral. Its chemistry is Sodium Calcium Aluminum Silicate.  Moonstone looks similar but is an Orthoclase/Albite feldspar mineral. Its chemistry is Potassium Sodium Aluminum Silicate.

They are both genuine gemstones that look very similar, and both are beautiful.  To ME, the Rainbow Moonstone with its more intense color display is far more beautiful, but that's just my opinion.