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LocalitiesWashington Pass, Golden Horn Batholith, Okanogan County, Washington, USA

23rd Jun 2012 04:20 UTCSteve Stuart Expert

I finally started breaking up and examining some material I obtained at the 2012 PMA Symposium in Redlands, CA. Need help with IDs of the minerals shown in the attached images.

Thanks for any and all input!

Steve Stuart

23rd Jun 2012 07:14 UTCDan R. Lynch

The bottom two photos look like gadolinite to me, comparing it to one of my gadolinite-(Ce) specimens from Washington Pass and to other photos in the locality gallery. Not certain though.

23rd Jun 2012 08:54 UTCPeter Andresen Expert

Wild guessing, WP is not a locality I'm very familiar with, but still they remind me of zircon. Try imagine a tetragonal pyramid {111} and the prism {100}/{010}. Quite easy to be confused with a garnet, which I've done several times. :-)

Peter

23rd Jun 2012 09:44 UTCJohan Kjellman Expert

zircon

23rd Jun 2012 12:22 UTCSteve Stuart Expert

Thanks! All images are about 2 mm FOV in length. My first thought for # 1 was a garnet of some kind, but I didn't see any of the garnet group listed on Mindat for Washington Pass. The last two images are of the same crystal. Gadolinite-(Ce) came to mind after looking at the Mindat gallery, but I wanted some other opinions.

So, to summarize so far-

#1 could be zircon instead of garnet

#2 and #3 could be gadolinite-(Ce)

Any other suggestions?

Steve

23rd Jun 2012 16:34 UTCJohan Kjellman Expert

1, 2 and 3 zircon for their apparent tetragonal symmetry. I cannot, as much as I would, match them with the gado-images in the gallery. But to be sure you should have someone familiar with the locality verifying this. Saul Krotki is probably your man..

cheers

23rd Jun 2012 19:55 UTCSteve Stuart Expert

I'll check for fluorescence this evening. See if that adds anything.

23rd Jun 2012 22:35 UTCBart Cannon

I have spent considerable time collecting Washington Pass, starting in 1967.

The lower two photos look as though they are hexagonal prisms without pyramidal terminations.

My guess is bastnaesite / fergusonite / parisite.

The dark cube like crystal in the upper photo is not like anything I've seen before from Washington Pass.

The micro mineral experts for Washington Pass are Randy Becker, Rudy Tschernich, Russell Boggs and Bob Boggs,

Perhaps I can nudge them toward this post.

Bart Cannon

23rd Jun 2012 22:44 UTCWilliam C. van Laer Expert

I vote for zircon in all three pictures...Bart, I just don't see a cube in the upper photo, and no hexagonal form in any others...I have found many similar specimens with the same identical form and every one turned out to be zircon.

23rd Jun 2012 22:58 UTCKeith Wood

Sphalerite

Zircon or Xenotime

Zircon or Xenotime

Just my guesses based on appearance only, never having collected there.

24th Jun 2012 00:31 UTCSaul Krotki Expert

Here are a few zircon crystals from Goldschmidt's Atlas. You can see how

various photo angles would emphasize different face shapes. In one orientation,

you have an obvious tetragonal zircon and in another, you have a zircon that may leave the

impression of an isometric garnet.

There are no garnets at Washington Pass (...a budget description for a locality.

since many of the celebrated specimens are found miles from the pass...but that

is another story.)

Gadolinite! No way! These are zircons! I have collected the most remarkably

flattened crystals in the GHB. Sent a few to Bart Cannon for ID. Yup, zircons

"that look like wulfenite," as Bart reflected!

Photos can make deceptive impressions unless the crystals are oriented in the image

to represent their species symmetry. You know...like a Dana textbook image!

24th Jun 2012 00:51 UTCBen Schumer

The crystal in the first picture could be a betafite group mineral, based on the dodecahedral (?) habit and the red halo around it. Betafite group minerals in the Zapot Pegmatite, MIneral Co., NV show similar halos (radiation damage) in feldspar and any quartz nearby is smokey. I am unfamiliar with Washington Pass mineralogy, though, so I don't know if the paragenesis would support the betafite idea.

24th Jun 2012 01:43 UTCBart Cannon

Only a fool such as myself tries to identify a mineral from someone else's photograph.

But I stand by my opinions.

The upper photo shows a dark roughly cubic crystal, and the others are not simple tetragonal prisms. Plus the fractures and coloration are not seen in zircons from Washington Pass.

Back to the color chart project.

Bart

24th Jun 2012 01:51 UTCBart Cannon

The bigger point.

I'm not even sure that these specimens are from Washington Pass.

Bart

24th Jun 2012 02:12 UTCSteve Stuart Expert

I have to go by what the labels says on this material from the micromineral symposium in Redlands, CA thsi past January. Also, I have found blue fibrous riebeckite on specimens from the same lot, so I think that it is indeed Washington Pass material.

24th Jun 2012 03:04 UTCSteve Stuart Expert

Here is a shot down the c-axis as suggested by Saul Krotki. Tetragonal (distorted) or orthorhombic? No observable fluorescence under LW, MW or SW UV light.

Now for the bad news! My specimen now looks like a mouth with a missing tooth! In closing the micromount box , I dislodged the crystal and it is lost. There is a smaller crystal of similar habit still there, but it is not nearly a photogenic.

Merde!

Steve

24th Jun 2012 03:13 UTCBart Cannon

Blue, fibrous amphibole would be good evidence for a Washington Pass origin for THAT specimen.

I shall respectfully retire from this discussion until I have the specimens in hand under my stereo-microscope.

Bart

24th Jun 2012 03:53 UTCDouglas Merson 🌟 Expert

Zircon for all three.

24th Jun 2012 11:29 UTCJohan Kjellman Expert

told you Saul was your man...

cheers

24th Jun 2012 23:12 UTCSteve Stuart Expert

Thanks for all the responses! I'll go with zircon. Although I mourn loss of the crystal shown in #2 and #3 images, I have found a few more zircons in the material I obtained in Redlands last January. See below (all about 2 mm FOV):

Regards,

Steve

26th Jun 2012 04:15 UTCDouglas Merson 🌟 Expert

Steve,

The small black crystals on the zircon 5b have been shown to be anatase based on work by Dr. Don Howard. The whitish plate on the the prism face of 5b may be xenotime.

Doug

27th Jun 2012 00:29 UTCSteve Stuart Expert

The white coloration looks more like a surface feature to me rather than a plate attached to the zircon. A Mindat image of anatase on zircon leads me to the ID as well. I've added some zircon images to the Mindat gallery for Washington Pass.

Again, thanks for all the resposnes!

Steve

4th Jul 2012 02:23 UTCSteve Stuart Expert

A few more Washington Pass images. The last one looks like siderite coated with malachite or perhaps a chlorite group mineral. Would welcome opinions on the first two. Thanks!

Steve

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