Thursday, May 16, 2013

I got a rock... (part 1)


For those of you who are younger than i am (that would be most of you) the headline is from a Charlie Brown (tm) Halloween special, where everyone else gets candy and Charlie Brown looks in his bag and says: "i got a rock.." Poor Charlie Brown.

For many of us, though, we would be delighted to get a rock. rocks are wonderful!  Rocks of some kind are important in jewelry.  Yes there are technical differences between rocks, and stones, but lets cut to the important stuff:

what the heck is it?  (part 1) and how do i take care of it? (part 2)

the two questions are related. some stones used in jewelry are very delicate, some are "hard as rocks" and if you do not know what it is you have, you have to assume its delicate.

The questions that tell you "what the heck is it?" are:

What kind of rock is it?
What was done to your rock?

What kind of Rock is it?

You would think this would be an easy question to answer, wouldn't you?  If it says a single word , like "Amethyst" or "Topaz" then it generally is exactly that (but not always).  The problem comes up when the name is descriptivce and has places or other words attached to it.
"Picture Jasper"
"London Blue Topaz"
"Korean Jade"
"Mystic Topaz"

so what are they?  Are they Jasper, Topaz, and Jade? or something else entirely?  Whenever you see a compound word used to describe a stone, you need to do a bit of research to figure it out.

Picture Jasper is a type of Jasper (ok, its Jasper) that has natural markings (ok, its not created) that make "pictures" or look like images or landscapes. (ok.. this is a straight forward desciption of what THIS kind of Jasper happens to look like)

London Blue Topaz is a Topaz (ok, it is a topaz) that has been irradiated (we will cover that later) to create a specific shade of deep blue (color ). This name is a "trade name" (oh, its a marketing name, and probably trade marked).

Korean Jade is a type of Serpentine (woah! its not Jade) with a specific coloring, found in many places worldwide... (not Jade, but Serpentine, and should be cared for as "Serpentine")

Mystic Topaz is really Topaz, (the stone is Topaz) but has a treatment (see next section) that is very delicate.

Get the idea?  A compound name may simply be descriptive, or tell you why this type of Jasper (for instance) is different that the other kind, but it could mean that it needs different care or that it is, in fact, NOT the stone you think it is!

Obviously if you want to take care of your jewelry properly you need to know what kind of rock it is first!

Some types of stone are very sensitive to light, some to heat, some to chemicals (like swimming pools and cleaning products) and a few , a VERY few, can go from a lying out in the sun at a swimming pool to cleaning the floors and come out just dandy.

Knowing what your stone actually IS is important to caring for it (and cleaning it) properly!

What was done to your rock?

 Now it gets complicated.  Gemstones, and other pretty rocks, are subjected to all sorts of treatments to make them "prettier" to get rid of flaws, or to let them survive encounters with things like chlorinated water.
What treatments are "acceptable" and which ones are fraud, can be a very tough argument.

Heat Treatment: this is one of the oldest ways of improving or altering a stone.  We have documentation of this being done back to the earliest written records, and we have evidence of it from before written history.  There is nothing wrong with this, although of course it should be disclosed to the buyer.
Almost all Citrine, Carnelian, and Amber on the market today has been heat treated. This is usually permanent, and stable.

Dyeing: is a treatment that is considered usual and normal in some stones, and i dislike intensely. 
Real stones can be dyed to enhance their color or to make them look totally different.  Often this means "make them look like a more valuable stone". Turquoise, as an example, is often imitated by dyeing  various stones that are worth far less money, but real (if poor grade) Turquoise is often dyed to give it a better color!  Dyed stones can lose their color if exposed to the wrong chemicals or cleaners.

For myself, personally, i only use dyed stones that CANNOT be mistaken for something else.

dyed Magnesite
The above picture is dyed Magnesite.  This stone (and it is a real stone) is naturally sort of putty colored, with inclusions in a kind of crackle pattern.  It is often used to make imitation (fake) Turquoise or Lapis, because the pattern on the stone (which doesn't take dye) mimics the look of a real Turquoise.  I will not buy it in colors that mimic natural stone, because i don't want anyone mistaking it for something it is not.  It makes a very pretty piece of jewelry, though...
Magnesite, dyed blue, wrapped in three metals

Irradiation, something that can happen naturally deep in the earth, is often artificially used to create or change a color in a stone. Topaz is the best example of that.  ALL blue Topaz is irradiated.  A very very few pieces were naturally created by radiation in the earth, but unless you curate a museum, or dig your own, assume all blue topazes are real Topaz that has had their color altered.  This treatment is permanent and the colors *usually* do not fade.
London Blue Topaz. The color is created by radiation

Filling, Oiling, and Stabilizing:  Here is where it gets increasingly complicated.  Each of these types of treatment can be good, or bad.  It can mean something very simple, or a complete change in the stone.

To start with the simplest one, Stabilizing, this means a resin has been forced into the stone at high pressure.  it changes the characteristics of the stone, a lot.  On the plus side it can take a fragile stone like Turquoise, and make it more resistant to chlorine, and other hazards, but it can also be used to take "waste" Turquoise and pass it off as good Turquoise. A lot of whether this is acceptable or not depends on if it is properly labeled, and whether any color was added.

Emeralds (and every member of the Beryl Family) naturally have very small cracks in the stone.  In Emeralds these cracks are filled by "oiling" which makes these natural cracks less visible. This is an accepted and usual practice...UNLESS they also use color (dye) to change the apparent color of the stone... and you wont be able to tell. This is one reason why buying a GOOD Emerald is a tricky purchase

Assembled or Reconstituted:  This means that bits of a real stone have been fused in some fashion, often with resin.  This is sort of like a fish stick, or a chicken nugget, compared to a real fish fillet or chicken breast..  I wouldn't mind this, except that all to often the stones end up being sold, and re sold, and gifted, and somewhere along the way the fact that this is NOT the real deal gets lost.  This is most commonly seen in Opals, Amber and Turquoise.

Coated:  Applying a coating to the surface of a stone can make some incredible effects.  It is, however, able to fade, or be scratched off, and is usually sensitive to chemicals. "Mystic Topaz" is coated... and really quite lovely, but too delicate for me.

a very well cut and treated Mystic Topaz, from Gemselect

Obviously you also need to be aware of outright fakes.  If you think something is a pearl, and its actually glass, plastic, or resin, then that is a fake not a "treatment".  That more or less falls under "what kind of rock is it".

Knowing what kinds of fakes are commonly available for different stones will help you identify potential problems.

Links and Sources:

Jade earrings and the trade routes

My Etsy shop

Gemstones, By Cally Hall (book): an easy to read book, with color pictures, that is fairly accurate.

Gemstones of the World: by Walter Schumann (book): intended for someone with more background in geology or gemology, it is one of the best for identifying possible fakes, and which stones can be confused.

"I got a rock... (part 2)" blog post.

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