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Identity HelpUnknown on smoky quartz

21st Sep 2018 00:17 UTCtodd Van Duren

I received this specimen today. No locality, (waiting for a reply from the sender). Yellow mineral was labeled as calcite but it is clearly not. Hardness is ~3.5. No clear indication of cleavage from those crystals that are broken; perhaps indistinct at best. No fluorescence.

My first thought was adamite based on crystal morphology, but the association seems wrong. Second guess is perhaps stilbite. The luster is certainly suggestive of stilbite or heulandite.

The quartz itself is rather distinctive. Primary quartz crystal has been partially covered by a thin layer of a greenish-white material, which has partially healed over with another layer of quartz. The yellow unknown appears to have formed after the final layer of quartz and grows on top of both the healed quartz and the greenish-white material.

Any thoughts on ID or locality would be much appreciated.

21st Sep 2018 00:46 UTCRuss Rizzo Expert

Hi Todd,

The larger crystals are stilbite. I'm not sure about the greenish-white material. Getting the location for the specimen will be helpful.

Russ

21st Sep 2018 00:54 UTCtodd Van Duren

>

> Getting the

> location for the specimen will be helpful.

No suggestions? Mindat searches are drawing a blank.

21st Sep 2018 01:03 UTCIan Nicastro

I've found stilbite with smoky quartz in several pegmatite deposits in southern california, but the stilbite is bone white and small usually. Searching mindat I found a location in poland that has yielded smoky quartz with yellowish stilbite: https://www.mindat.org/photo-662808.html

21st Sep 2018 01:28 UTCRuss Rizzo Expert

Poland would be one of my top guesses as well. It could also be from China. About 9-10 years ago I had a few smokies from China that had yellow stilbite associated with them.

21st Sep 2018 01:51 UTCtodd Van Duren

The specimen did come from a Chinese dealer, so China seems likely. Unfortunately a search of Stilbite photos, keyword 'quartz' and Quartz photos, keyword 'stilbite' did generate anything comparable from China.

21st Sep 2018 02:03 UTCRuss Rizzo Expert

The specimens that I mentioned previously could've had stellerite on them and not stilbite. I can't find anything in my records that tells me where in China they where from. It was a long time ago and I only had them for a short time. I do remember that my specimens also had ~~opal-AN and epidote/clinozoisite associated with them.~~

Edit: Memory can be poor sometimes... it was chabazite & laumontite.

21st Sep 2018 02:22 UTCKevin Conroy Manager

Wouldn't it be interesting if the white crystals were bertrandite?

21st Sep 2018 02:36 UTCtodd Van Duren

Kevin Conroy Wrote:

-------------------------------------------------------

> Wouldn't it be interesting if the white crystals

> were bertrandite?

Are you referring to the fine acicular crystals? I assumed natrolite or some other zeolite, >if< the yellow mineral is indeed stilbite (sp).

I have yet to look at the specimen under anything but 10x.

21st Sep 2018 02:57 UTCKevin Conroy Manager

Yes, I did mean the microscopic acicular crystals.

21st Sep 2018 11:19 UTCJohan Kjellman Expert

possibly Strzegom/Striegau, Poland

21st Sep 2018 15:10 UTCUwe Kolitsch Manager

Stilbite/stellerite.

21st Sep 2018 16:38 UTCtodd Van Duren

OK, the locality has been given to me as Tibet Autonomous Region. Certainly a poorly documented area for sure.

I must say the photos of Strzegom material does look very similar. The morphology of the quartz, the color of the stilbite, the assemblages. I'd be more likely to believe Strzegom than 'Tibet', despite the fact the specimen came from a Chinese dealer.

21st Sep 2018 16:47 UTCtodd Van Duren

If Strzegom is correct, the white acicular mineral could possibly be bavenite.

21st Sep 2018 17:33 UTCA. M.

If it's from Strzegom, the dark green (almost black) mineral would be strigovite (a kind of chlorite group mineral; the name is from Strzegom - Latin name "Stregovia", German "Striegau", where was it discovered), and yes - the white mineral would be bavenite, as Todd said.

22nd Sep 2018 06:25 UTCV. Stingl

Why should a Chinese dealer sell pieces from Strzegom, when he can get same or better quality much cheaper? My guess is one of the quarries around Rhizao, Shandong.

22nd Sep 2018 15:37 UTCtodd Van Duren

Why do Chinese dealers sell Moroccan vanadinite and Congolese malachite? Why do US dealers sell Chinese Fluorite? Why do we all put pepper on our food?

We do live in a global economy and things do have a tendency to filter around.

This piece in particular appears to have been a one-off in the dealer's offerings. One can imagine myriad ways a singular curious but generally ugly specimen might migrate from hand to hand around the planet. Pity minerals don't come with passports.

Considering the morphology of the quartz and the general assemblage of the piece, I still think Strzegom is a more likely source.

At the very least it has been a fun little puzzle for $2.25US.

23rd Sep 2018 00:41 UTCRuss Rizzo Expert

Todd,

I don't think your specimen is from Poland. I believe it is from China.

Click on this link & this link

Russ

23rd Sep 2018 01:24 UTCKevin Conroy Manager

I'm not 100% convinced that the yellow crystals are stilbite. They very well could be, but to me the color and shape are a bit off. Todd, how accurate is the color in the photos? What if they're mimetite? The reason I ask is because this reminds me of some specimens that I saw (I think from a find in the 1980's or 1990's) from Kara-Oba. This specimen should probably be analyzed to help sort things out.

23rd Sep 2018 02:00 UTCRuss Rizzo Expert

The crystals on Todd's specimen are the same as on the specimens that passed through my hands. The crystals are either stilbite or stellerite. My id was good enough for Michael Wise to purchase one.

23rd Sep 2018 05:47 UTCtodd Van Duren

The color in the photo is very accurate in comparison to the actual piece. Perhaps a little over saturated, but the color is exact. Think cantaloupe orange.

I really don't think it's mimetite. The cross-section is distinctly orthorhombic or tetragonal; there is absolutely no suggestion of hexagonal symmetry.

Russ, thanks for the link. Pity the mindat page for Tongbei is not more fleshed out. Pity too the images on Chino Neolithic page aren't a bit sharper

and color balanced. Is this your page? If you have handled these specimens, what would you make of the accessory minerals on my piece? What is

the acicular mineral on this piece: http://www.chinaneolithic.com/en/stores/view.asp?id=610

Yes, it would be great to have this piece analyzed. Unfortunately I don't have direct access to anything more than mineralogy texts, a loupe, experience

and a few chemicals. It will have to go into the 'to have analyzed' pile along with a few other things that need identification, (uranium unknowns from

the Congo, etc.)

23rd Sep 2018 06:16 UTCRuss Rizzo Expert

Hi Todd,

I have no affiliation with China Neolithic. I just did a quick internet search and they were the first of many that came up.

Tongbei doesn't ring a bell as far as the location. My memory tells me that it was Chenzou, but I'm not certain that is where mine were from. And I wouldn't be 100% sure about your specimen or others on the internet. I've been fed a lot of misinformation over the years from Chinese dealers. Afghani & Pakistani too. Mostly,I think, to misdirect others who might also want to exploit what has been found.

The 2 specimens that I had were only in my possession about a week or so at Tucson in 2009 or 2010.

My guess on your white acicular crystals, and only a guess, are that they are laumontite. If you can remove a few of the crystals from a spot on your specimen that won't be noticed, you can test for laumontite by trying to dissolve it in a small amount of HCL. If it is laumontite it will form a gel.

Russ

23rd Sep 2018 19:46 UTCKevin Conroy Manager

Todd, thanks for the verification of the color and the additional info about the crystal shape. I'm comfortable now with the stilbite/stellerite ID.

Russ, I was just trying to get a bit more data on the crystals. Sometimes it's hard remembering past finds/crystals when they're not from larger documented finds. I also think you're right on about the white crystals being laumontite.

24th Sep 2018 01:35 UTCtodd Van Duren

Tongbei was listed for those specimens I thought looked most similar. When I say similar, I mean similar looking stilbite. The assemblages look decidedly different, but it really is hard to tell because the resolution is so low.

25th Sep 2018 09:48 UTCRuss Rizzo Expert

Kevin Conroy Wrote:

-------------------------------------------------------

...Sometimes it's hard remembering

> past finds/crystals when they're not from larger

> documented finds.

Sometimes its hard enough just remembering and it ain't getting any easier with age.

20th Nov 2018 00:58 UTCRuss Rizzo Expert

Update....

Found a picture of one of the specimens that passed through my hands.

It turns out that Chenzhou is the correct locality for these specimens. Wish I had a more accurate locality than that. But it is better than nothing at all.

Cheers,

Russ

11th Feb 2019 13:21 UTCEligiusz Szełęg Expert

Hi,

Your samle looks like Strzegom smoky quartz with stilbite-(Ca) and laumontite

regards

Elek

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