Re: I think it's a yellow sapphire
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Agate or quartz, pretty sure.
If it was sapphire the yellow colour would probably have trigonal colour zoning.
I do cabochon cut and facet as a hobby, but am located in Sweden. PM me with questions if you like.
If you'd like to keep it within the US contact gemsbyjennifer;
http://www.gemsbyjennifer.com/
They have a lab to test it and a workshop to cut it.

I know and trust them.
Overseas cutting (often Thailand, China etc) makes me sceptic.
Getting it cut in those countries is a gamble. Quality of the cut can be good or really, really bad. Mostly the later.
Ask anyone who does costume jobs and I bet you'd get the same answer!
I see a crack in there - use a small hammer and break it open, could give an important hint.
Either way it should yield at least 2 stones, can't cut one big due to the crack.
A steel knife just and just is softer then quartz I believe, 6.5 or so. So quartz should not get scratched.
As for worth - no idea but don't expect to get rich any time soon, lol.
Most of similar clarity (cabbing rough) is usually at say 10$/ carat and that often being with a star effect..
Without star it would be lower, and that are not wholesale prices.
10 grams is 50 carats.
Only the yellow colouring and/or locality could push it up a bit.
GG,
Don't mix up kt (Karat - used for gold alloys) and ct. (carat - 0.2 grams)
