Is this Turquoise?

[tribeunited]

I like this one sooooo much - but what the heck is it?


Is this turquoise, or something else???

[rockjunquie]

Probably chrysocolla and tenorite.   vegasjames?

[chris1956]

Wow!

[tribeunited]

thanks rockjunquie - I'll wait for the resident blue expert to weigh in before labeling it.

chris1956 - I know right? I keep staring at these photos!!! So pretty!!! I LOVE blue stones.

[vegasjames]

Possible, but there are various minerals that can look like turquoise. It can be virtually impossible to tell from a pic. Would either have to run some tests on it, or if you knew what mine it came from you can find out what minerals are derived from that mine on Mindat.org.

[tribeunited]

Nov 11, 2024 2:31:27 GMT -5 vegasjames said:

Possible, but there are various minerals that can look like turquoise. It can be virtually impossible to tell from a pic. Would either have to run some tests on it, or if you knew what mine it came from you can find out what minerals are derived from that mine on Mindat.org.

I have no idea where it came from.  

What tests would you run to determine blue minerals? 

[vegasjames]

Nov 11, 2024 11:05:09 GMT -5 tribeunited said:

Nov 11, 2024 2:31:27 GMT -5 vegasjames said:

Possible, but there are various minerals that can look like turquoise. It can be virtually impossible to tell from a pic. Would either have to run some tests on it, or if you knew what mine it came from you can find out what minerals are derived from that mine on Mindat.org.

I have no idea where it came from.  

What tests would you run to determine blue minerals? 

Hardness of the blue areas would be a good start.  Turquoise is harder than chrysocolla unless chalky.

More definitive would be to do a phosphate test since turquoise is a phosphate mineral and chrysocolla and "silicated chrysocolla" are not.

If you could isolate just some of the blue, a density test can also help as turquoise has a higher density than chrysocolla.

[tribeunited]

Thank you vegasjames.

I've avoided hardness tests on Chrysocolla so far because it has such a wide range - hardness alone won't cut it! I see that you said "a good start"- I finally get it, there are multiple steps to the test. You just taught me again. Thank you sensei!

For follow up tests, I'll need to do more reading on phosphate testing before I go further with that one.

I did some reading about the density test last night. I think I fully understand the test and I want to try it. Is there a minimum mass/weight you recommend to get accurate results? It seems like it would depend on the volume of the tube used. Does that sound about right?

Thanks again Mr. Vegas!

[vegasjames]

Nov 12, 2024 12:50:51 GMT -5 tribeunited said:

Thank you vegasjames .

I've avoided hardness tests on Chrysocolla so far because it has such a wide range - hardness alone won't cut it! I see that you said "a good start"- I finally get it, there are multiple steps to the test. You just taught me again. Thank you sensei!

For follow up tests, I'll need to do more reading on phosphate testing before I go further with that one.

I did some reading about the density test last night. I think I fully understand the test and I want to try it. Is there a minimum mass/weight you recommend to get accurate results? It seems like it would depend on the volume of the tube used. Does that sound about right?

Thanks again Mr. Vegas!

Real chrysocolla is actually very soft. One problem though is that people tend to call any unidentified copper mineral, and even mixes of copper minerals, "chrysocolla"  leading to a lot of confusion. I have even seen malachite and stones very obviously not chrysocolla still being called "chrysocolla".  That is why I prefer the term copper ore until actually identified.

Actual chrysocolla, a hydrated copper silicate, is actually very rare. Yet as often as we see copper stones being called "chrysocolla", you would think it is common as water.

Then there is the stone "silicated chrysocolla", sometimes refereed to as gem silica, which IS NOT chrysocolla. It is a chalcedony (cryptocrystalline to microcrystalline quartz) stained by copper salts.

Phosphate testing is pretty simple. Get a phosphate test kit, which if I recall right is ammonium molybdenate. Take a sample of the blue and dissolve it in hydrochloric acid. Crushing it can help speed up the dissolving.  I then neutralize the acid. I personally use calcium oxide (slaked lime), but baking soda should work. Then use the test kit to test the solution. The presence of phosphate will form a turquoise blue sediment.

There are a couple of ways to do a density test. The way you are referring to uses a graduated cylinder, checking water displacement. Being the sample will be so small, you will want the smallest graduated cylinder possible.  Smallest I have is 10ml, not sure if they come any smaller. Smaller the better in your case though for accuracy since the sample will be so small. Make sure you only use the blue part of the stone. None of the matrix.

[rockjunquie]

You've got me calling most copper mixes "copper complex".

[Pat]

Whatever…. It’s beautiful!

[chris1956]

Nov 12, 2024 17:44:01 GMT -5 Pat said:

Whatever…. It’s beautiful!

  Put a high $ amount on that baby.  

[tribeunited]

Thanks again vegasjames. I'm going to get a phosphate test kit.

chris1956 - This ones a keeper! Staaaarrre

[Tommy]

Just to add to the good info given already I've had similar material that was id'd as "chrysocolla in quartz." Your's is way more vivid blue than what I've seen though.