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Let's Rock => Identifications of Materials => Topic started by: liveoak on October 11, 2019, 06:37:58 AM

Title: what is it ?
Post by: liveoak on October 11, 2019, 06:37:58 AM

Hi, I hope someone can help me id this one.

I cut a cab from a slab I bought at a gem show last year , just to see what it would look like polished.
I'm not sure what it is, but my husband thinks its some kind of Jadeite ??

It does have some translucent areas & it's an overall green - gray - white appearance.

Any ideas???

Thanks, Patty

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Title: Re: what is it ?
Post by: rocks2dust on October 11, 2019, 12:17:31 PM

I can think of a few things that can have that appearance, including serpentine, prehnite, marble. You might try a Mohs scratch test (https://geology.com/minerals/mohs-hardness-scale.shtml) and an acid test on a scrap piece to narrow it down further.

Title: Re: what is it ?
Post by: lithicbeads on October 11, 2019, 03:05:41 PM

Definitely not jadeite nor nephrite .
Looks like chert to me.

Title: Re: what is it ?
Post by: liveoak on October 12, 2019, 04:14:56 AM

Thank you both.
I'll see about doing a Mohs test, maybe that will narrow it down.
I'll report back what I figure out, once the Mohs test samples arrive :-)
Patty

Title: Re: what is it ?
Post by: liveoak on October 14, 2019, 06:41:20 PM

Ok, I got my little Mohs hardness kit, and I know that it's definitely harder than mohs 7 ( quartz) and maybe as hard as 8 - but I knew it was hard when I cut it- but I'm at a loss to what it is.
That's all I got
Thanks for any suggestions,
Patty

Title: Re: what is it ?
Post by: Ryaly2dogs on October 14, 2019, 06:57:14 PM

I am impressed you appeared to use a rock scroll saw on something that hard!

Title: Re: what is it ?
Post by: liveoak on October 14, 2019, 07:08:34 PM

Actually , I cut it with a diamond band saw.
But grinding on my flat lap, it seemed harder than anything I had cut so far.
Patty