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Identity HelpPhenacite

7th Feb 2017 04:56 UTCJames H James

I recently found a specimen i believe to be phenacite and would like some help identifying it. I found it in colorado

Mt. Antero.

7th Feb 2017 12:58 UTCReiner Mielke Expert

Do the hardness and SG match phenacite?

7th Feb 2017 13:52 UTCHarold Moritz 🌟 Expert

Phenacite crystals from there typically show a rather flattened rhombohedral form, so your piece looks right, as does the luster and color. As Reiner suggests, check H and SG and also put a drop of vinegar or lemon juice on it to see if it fizzes and if so it would be calcite.

7th Feb 2017 18:19 UTCJames H James

It did not fizz when i put the vinigar on it.

I havent tested the SG or H of it yet

And thankyou for your support. I apprecite the people and this website for their support.

7th Feb 2017 18:21 UTCJames H James

Also i was wondering by just looking at it, what do you think it would sell for if it is indeed phenacite?

7th Feb 2017 18:43 UTCBob Harman

JAMES, Welcome to Mindat! If you wish a specimen valuation, I suggest putting the pix and valuation question onto the "valuation" thread on this website.

I also suggest having your specimen analyzed prior to asking for valuation. Personally I wouldn't touch an example such as yours without an accepted analysis as so many low end and inexpensive minerals look quite similar. CHEERS.....BOB

7th Feb 2017 19:14 UTCJames H James

Thank you. I am new to this community and ive just been holding on to all these specimens without reaching out for advice. I will get the rest of the info relating to the H and SG

8th Feb 2017 13:47 UTCHarold Moritz 🌟 Expert

We're always glad to help ID things. Good photos a must, yours are good enough. But anything you can tell us up front about the non-visual properties like hardness, density, cleavage, reaction to acid, and of course, where it is from or what geo-environment it formed in (if known) is critical. Helpful to us for you to find these out first, then put that info into initial post, if you have not figured the mineral out by then. Look through the mindat photos from the locality (it does appear similar to other phenkites from Mt Antero), or of alternate minerals you think it might be. Always assume at the start that it is a common mineral (phenakite is not - from the pix, with no other info, it could be calcite, which is common), but by recording the mineral properties it displays - and locality info - demonstrate that it may be something rarer. We are, of necessity, a skeptical bunch. (The only other mineral listed on mindat from Mt Antero that may crystallize with a rhombohedral form is calcite, which you have ruled out). In the end, especially if potentially rare or valuable, analytical testing may be needed to convince others (buyers or mindat managers), especially from a loose crystal like this one that is not sitting on matrix, or with other minerals, typical of the locality. But if you can show it to others who are familiar with crystals from there, that may be sufficient in this case.

8th Feb 2017 14:31 UTCPeter Slootweg 🌟

To my eyes the specimen is just a piece of quartz. The second photo clearly shows a larger and a smaller rhombohedral (pyramid) face and prism faces with the usual horizontal striations. There is nothing to suggest it would be Phenacite exept for the locality where it was found. As mentioned, check hardness and SG to be sure.

8th Feb 2017 14:58 UTCHarold Moritz 🌟 Expert

It could be. Does seem a bit large for a rhombic phenakite from there, too.

9th Feb 2017 02:12 UTCJames H James

I did a simple test by taking that specimen and a quartz crystal and made a scratch on a face of the quartz. So i dont know if that helps with finding out the hardness of it. I also found a nice specimen that im having trouble identifying, near the area i found the specimen above.

9th Feb 2017 02:35 UTCWayne Corwin

smoky quartz crystals

9th Feb 2017 02:54 UTCJames H James

I was wondering what the mineral that is surrounding the small smoky quartz?

9th Feb 2017 03:26 UTCJames H James

Here is one more pic of the back

9th Feb 2017 03:28 UTCWayne Corwin

Looks like earlier generation of quartz (tu)

9th Feb 2017 20:00 UTCMichael Wood

James, if the first mystery crystal that you showed scratched a quartz crystal, then from the crystal's habit (appearance), location and hardness (>7), then it is extremely likely to be phenakite - nice one!

By the way I did the same test on a specimen from the Cairngorms (Scotland) that was in my drawer for about seven years before I tested it, and it scratched a quartz crystal... until then I had thought it was a funny looking albite crystal!

Your second specimen I say is a small smoky quartz crystal with feldspar (probably microcline feldspar, otherwise could be orthoclase feldspar).

The clear sparkly mineral could be either an overgrowth of albite feldspar, quartz, or even phenakite... your hardness testing is a good technique and your photo's are good :-)

Well found; good findings!

9th Feb 2017 20:15 UTCHarold Moritz 🌟 Expert

I agree with Michael, that the phenakite should scratch the quartz.

The newer photos look like smoky quartz on albite, note the striated appearance and triclinic shape that are characteristic of pocket crystals of albite (unlike microcline), which is very typically lining the pocket walls. I think the glassier part is just more albite overgrowth.

9th Feb 2017 21:20 UTCMichael Wood

I agree with Harold! :-)

I forgot you can zoom in on the photo, so I took a closer look...

11th Feb 2017 04:38 UTCJoel Dyer

Hi All,

I have been wondering why the larger "phenakite" at the top couldn't just be analysed and a sure answer got quickly, cheaply and easily. Phenakite as the "fooler" mineral with varying crystal habit surely can look like a lot of other minerals, and vice versa?

Just a humble thought crossing my mind...

Cheers,

7th Mar 2017 08:09 UTCEligiusz Szełęg Expert

Phenacite should have lines (striations) paralel to the prism.

It looks like quartz.

Regards

Elek

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