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Identity HelpCan you identify this?

15th Jun 2005 10:03 UTCJohn Steenbergen.

I have been shoving this specimen aside for weeks now as i haven't a clue what and where it came from. It has lustrious black crystals on a base of sawdust coloured crystals,which are not pretty to look at,but interesting crystals like Cerussite.Have you any idea what and where this comes from ? It is one i have not encounterd before. Thank you John

15th Jun 2005 13:58 UTCsteve

John;

This is a WILD guess; bcs, I can't see the largest xls too well. If you can take the pic through someone's draftman's magnifier lamp, you might have better results bringing those up. Anyway, here goes: the black might be the melanite variety of andradite & the brown might be tremolite/actinolite OR diopside, much like the Asbestos material.

Does anyone here have material with such?

Your friend, Steve

15th Jun 2005 16:03 UTCUwe Kolitsch

Black garnet (or babingtonite?) + titanite? or diopside?

16th Jun 2005 08:20 UTCJohn Steenbergen.

Hi there good people, i have another picture ,perhaps this shows the crystal form a little better. Please don't look at the colour as it is a reflection of the background.The crystals are not that of a garnet as you can see .They are shiny black in colour

16th Jun 2005 09:17 UTCPete Nancarrow

Garnets can be black , and shiny; the lustre can be surprisingly bright in free-grown crystals from a vug, compared with most of the more familiar ones from schists or other metamorphic rocks. However I can't see enough of the crystal forms to comment on whether yours are garnets.



Pete N.

17th Jun 2005 14:06 UTCThomas

Nice specimen



Hmm, how about hematite ?



Greetings



Thomas

21st Jun 2005 06:39 UTCAlan Plante

Hi John



The photos alone aren't going to do the job, I'm afraid - too indistinct...



Any chance you could determine the luster and hardness? Maybe measure a few interfacial angles? (In some of the black xls I am seeing what looks like isometric shapes, in others I'm seeing hexagonal shapes...) And maybe you could get a streak from one of the black xls? This info would help a lot in narrowing down the possibilities. - Much more so than just photos.



Regards



Alan
 
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