Sunday, September 5, 2010

Quick Tests You Can Do to Test for Fake Gemstones

A golden pearl necklace.Golden Pearls via WikipediaThere is nothing wrong with fake gemstones. They are affordable and fun so long as they are never sold as the real thing. That would be fraud.

But did you ever wonder if the jewelry you bought or acquired was real? Or if you have got some of your bead supplies horribly mixed up and need to tell them apart?

Here are quick tests for genuine gemstones that don't require special equipment.

Glass vs Gemstone
Passing off glass as gemstones dates back to the invention of glass around 4000 BC. Even the Ancient Egyptians moaned about the practice in their papyrus writings.

An old test was to put the piece in the mouth. Glass will soon feel warm. Gemstones feel icy for a lot longer because they have higher thermal conductivity than glass. They take heat from your mouth so they themselves feel cold.

The other giveaway about glass is the presence of tiny air bubbles - if you can see them without the aid of a loupe. Pressed or molded glass beads may have visible seam lines.

Pearls
The time honored method of using the teeth to scrape the surface of a pearl actually works. Real pearls have a gritty feel whereas glass or plastic pearls will be very smooth. I've used this test many times at workshops when people bring in old family pieces. But as I don't wish to gross out anyone by putting Grandma's or Great Aunt's pearls in my mouth, I just run my fingernail over the surface of the pearl. Works.

Amber
Make a saturated salt water solution which means you add enough salt until it cannot dissolve further. Add the bead. Plastic ones will sink provided they are not hollow beads and full of air! Real amber floats. If you check my past historical post The Amber Fishermen, that's the reason why people used to net them from the Baltic Sea.

Another amber test is to rub it vigorously until it gets really hot. Sniff it. It should have a pine-like, aromatic smell because it is after all fossilized tree sap from around 40 million years ago.

If the amber piece includes an embedded insect or small creature, it should not be a modern species. The general common sense rule is if the price is unusually low, then suspect its origin!

Jet
Jet is 4-5 times older than amber. It is a kind of brown coal called lignite which formed from a type of fossiled tree. The star of Victorian mourning jewelry, jet has a number of imitators. If you rub real jet with fine sandpaper, the dust will be brown. Plastic beads like Bakelite will leave a black residue.

A very common fake jet is vulcanite which is rubber heat treated with sulfur. It also produces brown dust with the sandpaper test. So you have to insert a hot needle into the bead. There is no odor with real jet. A vulcanite piece will however bubble a bit and smell acrid.

Jade
There are actually two types of real jade - nephrite and jadeite. Long ago people didn't realize both were different types of minerals until a 19th century French mineralogist determined it.

The confusion continues as there are several other gemstones which look like jade - serpentine and aventurine quartz are two common examples. The situation gets really complicated when the word jade is carelessly used in the gemstone name such as Malaysia jade (dyed quartz), Transvaal jade (grossular garnet) and New Jade (serpentine).

There are two quick tests for jade you can do. One is to hold it up to a light source. You will see tiny fibrous or granular inclusions in real jade. Chrysoprase or Australia jade is a micro-crystalline gemstone so it will appear flawless.

The sound test is fun. If you strike jade with a glass rod or something metal, it should make a tinkling sound. Just watch this video to see a demonstration. Both tests have to be used in some cases.



References
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Original Post by THE BEADING GEM
Jewelry Making Tips - Jewelry Business Tips 

7 comments :

WildGift said...

very informative. Thanks!

d'Olivia said...

I'll have to save this post. I bought a bead stash through an estate, and was wondering if the amber was real. I'll try the salt water test. I guess I thought everything would float in strong salt water.

BetteJo said...

Good stuff to know, thanks Pearl!

Melissa Cox said...

This was great! Thank you for all of the wonderful information. It was great to find out that I actually have a real jade bangle in my collection.
Thanks again!
Melissa

Susan said...

Thanks...Great informative read!

Chrissi said...

love this article- but I have a set of green blue and pink(and I know they are)glass bracelets, same size as my nephrite bracelets and they tinkle too, when they are worn together, as do most of my agate ones- but looked at through a strong magnifier they have some fine lines within them, which give them a slightly silky look

Pearl Blay said...

Hi Chrissi,
You have what I think might be the "fruity" quartz which are man made glass or imitation gemstones. Some names include cherry quartz, blueberry quartz and pineapple quartz. They are cleverly made because they have color variations and fine lines within which give the illusion of gemstones.

But they don't have the feel of gemstones which are real stone. Try the warmth test holding a glass bracelet in one hand and your agate one in the other and see if you can tell the difference.

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