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Identity HelpWould love to know what this is!

25th Aug 2010 02:34 UTCMonica Ceretti

Hi all, pictured below is a 3" x 3" x 1" specimen that was given to me recently without any documentation. I have no idea what it is; I'm hoping someone here can shed some light on this.

As always, my sincere thanks.

Monica

25th Aug 2010 02:57 UTCRalph S Bottrill 🌟 Manager

Possibly a rhyolite breccia with lithophysae?

25th Aug 2010 06:38 UTCRock Currier Expert

Some people might call it an agate, but that would probably not be strictly correct. How hard is it. Can you scratch it with the tip of a pocket knife blade?

25th Aug 2010 07:26 UTCMonica Ceretti

I tried scratching this in multiple spots using the sharp tip of a metal letter opener. I applied a lot of pressure and while in a couple of spots I could see a faint trace of where the metal was in contact with the rock, I'm not sure I would describe it as "scratched." In handling the specimen more I did manage to dislodge a few very small bits of the specimen though I don't think these were the result of my efforts to scratch it.

I also neglected to mention that this sample weighs 3.75 ounces (or 106 grams).

M.

25th Aug 2010 13:39 UTCStephanie Martin

This material highly resembles what they call "leopardskin jasper" used for tumbling and lapidary. Commonly available from Mexico. If you google "leopardskin jasper rough" you will see a lot of examples.

stephanie

25th Aug 2010 15:00 UTCAlex Homenuke 🌟 Expert

Geologically, it shows multiple phases of silica deposition (quartz and chalcedony) and fracturing.

25th Aug 2010 16:19 UTCMonica Ceretti

Thanks all. I will definitely explore "leopardskin jasper" and see what more I can learn.

Monica

25th Aug 2010 16:38 UTCAnonymous User

Also try "ocean jasper".

k

25th Aug 2010 19:31 UTCAnonymous User

"Ocean jasper" typically has small pockets of tiny clear quartz crystals inside some of the "eyes". Are there any of those present? Plus the eyes are often green.

25th Aug 2010 23:08 UTCMonica Ceretti

Ken, a few of the eyes do appear to have very small clear quartz crystal centers. However, most appear to have dirty brownish-red centers surrounded by what I would describe as olive green or greenish-brown. Generally speaking, I would say the specimen more closely resembles the photos I've found of rough leopard skin jasper than it does those of ocean jasper, but I can certainly see why you suggested this possibility.

Thanks.

M.

25th Aug 2010 23:09 UTCPaul Brandes 🌟 Manager

Looks like the ultimate bonus question on a college petrology lab exam.........

"Get this one right kid, and you ace the class"!!! :D

28th Aug 2010 03:08 UTCLogan Babcock (2)

could it be crandalite? or whatever its called...

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