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[zurn]

Hello
can somebody tell me is this a new stone
I did a little research
discovered in Africa
but don't know when
and Ive never seen or heard of it
Sorry no pics
It is amazing when cabbed from pics Ive seen
I just came across it on Instagram there is a large group of pics there
looks like a cross of chrysoprase, Chalcedony , silica, maybe turquoise 
thanks
Antony

[gemfeller]

I think someone must have gotten a little carried away in the Instagram info if the description was about the material studied by GIA (below).  The material is chalcedony which is colored by *both* nickel and chromium which gives it a hue that's distinct from chrysoprase (nickel chromophore) and chrome chalcedony (chromium chromophore). 

Since it's cryptocrystalline quartz (chalcedony) it would be impossible for it to contain aquamarine (beryl) or crystalline quartz (citrine).  Here's the GIA run-down:

https://www.gia.edu/gems-gemology/winter-2015-gemnews-new-natural-color-bluish-green-chalcedony 

[zurn]

That explains that thank you
it does make for some nice cabs however
and id still like to get my hands on some

[irockhound]

To me it just looks like good quality Chrysoprase.  I love when they add titles to make something catchy.  Just think of the craze that happened when they dubbed the lowest grade Lapis "Denim Lapis", everyone had to have it and they had a hard time selling it before that.  Trade names always muddy the waters.

[Debbie K]

If you have encountered what I have, it's not exactly chrysoprase. It's too heavy for opal, too light for quartz. It would be more accurate to describe it as chrysocolla or "gem silica". My graduate gemologist friend confirmed what I found, and we were trying to get our sample into the GIA lab at the Tuscon show and ran out of time.

An acquaintance was selling it as opal, and I tested it because the weight wasn't right and I thought he had something better than he knew and was selling it too cheap. His stuff was coming out of Ethiopia and was more green than blue green and looks like chrysoprase at a casual glance. It's doubly refractive, so it's definitely not opal.

Debbie K

[ileney]

Is this related to the chrysopal coming out of Indonesia or is that stuff truly Opal? I have a rough piece that looks pretty uniformly dreamy pastel mint green. I posted it here a few days ago along with chrysoprase to show the color contrast.

[Debbie K]

Ileney:

I don't have any of the Indonesian stuff so I can't answer. If anyone does have some and a polariscope, opal will be singly refractive and chrysoprase or chrysocolla will be doubly refractive.

I did a specific gravity test on my Ethiopian stuff and it was in the range for chrysocolla; the hardness test had it leaning towards quartz, however.

My Australian chrysoprase shows strong extinction in a spectroscope in a range that indicates high nickel content; the Ethiopian stuff didn't.

Debbie K

[ileney]

Thanks  for the information Debbie,

I have been thinking of getting a polarsicope. I see JTV has some inexpensive (as well as more expensive) geological tools such as spectroscopes, polariscopes, dichroscopes, refractometers, microscopes, chelsea filters, hardness picks and the like. What are the essential tools you think one should have for identifying stones? I am making my birthday list! Do you know if I can get away with the basic versions or if they don't work well?

[Debbie K]

It depends on what you're going to ID with them. For rough, you're better off making a specific gravity scale and getting a polariscope and hardness picks. For gem ID, the refractometer is a must have. If you can buy one locally it might be safer, as they can be damaged in shipping. If the folks that sell them can show you how it works, so much the better! The dichroscope and chelsea filter are also more useful for gem ID. The spectroscope tells you less than the other tools.

Some of this equipment you can make yourself. Get a copy of Hanneman's Guide https://www.amazon.com/Guide-Affordale-Gemology-PH-D-Hanneman/dp/B01GSL7R7S/ref=sr_1_3?s=books&ie=UTF8&qid=1497241859&sr=1-3&keywords=hanneman. A friend and I made most of the equipment he describes in the book. The SG scale is particularly fun and useful.

If you crawl Craig's list sometimes you find old GIA tools for sale; sometimes quite inexpensive. These tools are really expensive new, so it pays to have patience in trying to acquire them.

If you get a refractometer, try to get one that DOES NOT have an internal light. Once the bulb burns out you have an expensive paperweight. The ones that use a flashlight are better, and it need to be an old fashioned small Maglight with a real bulb. You need white light to get an accurate read. The same goes for the microscopes.

If I think of more, I'll post tomorrow.

Debbie K

[ileney]

Debbie,

Thank you so much for all this information. As always, you have been so helpful.

[Debbie K]

Ileney:

I forgot the things I use the most! A blacklight and a loupe. The gem ID folks sell the expensive long and short wave lights, but I use the little flashlight all the time to see if things fluoresce. It's a great way to separate things quickly, like rubies and many diamonds and synthetics.

What do you want to ID? I got started on this by wanting to know how to determine if something was jade. For that, the best things would be hardness picks, SG scale and if it were cabbed and polished, a refractometer. To determine if it were bleached, dyed or stabilized, I'd need a good loupe or microscope, a spectroscope, chelsea filter and uv light. What you get depends of what you want to do.

This is a really good book, https://www.amazon.com/Gemstones-World-Revised-Walter-Schumann/dp/0806994614/ref=sr_1_2?ie=UTF8&qid=1497273923&sr=8-2&keywords=gemstone+of+the+world. It gives you lots of information on the characteristics of each gemstone and lots of pictures. I like that it also includes what each stone can be confused with, a really useful feature.

Debbie K

[ileney]

Many thanks again Debbie!