Any Clues ?

[kylehudson424]

 

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[DDancer]

Looks like a gypsum or selenium crystal in sandstone. Could even be a calcium related mineral.

 

[Eu_citzen]

DD, do you also see cleavage in the host-rock? Looks like calcite to me.

*Although uncertain of the actual crystal. First thought was feldspar-ish.

 

[DDancer]

Eu, yep. Calcite is a good thought as well. The crystal itself is to rhombic where calcite is cubit thats why I am more towards selenite or gypsum. The angle of the cleavage in the host rock is not right for calcite either in my opinion. Its an attractive piece though. Feldspar is pretty clean and often very glassy in appearance. It also cleaves sharply and the crystal here has a decidedly soft appearance with wear on it that shows no sharpness I expect of a feldspar.

 

[hvacker]

I think it's a Canadian dime.

 

[Dakota Sioux]

Looks like feldspar orthoclase crystals to me

 

[DDancer]

Yep thats a nasty looking feldspar Nope does not match whats shown. I mentioned a glassy appearance and that is apparent on your picture Dakota. Also very telling are the striations on your picture. Feldspar is very pronounced in most cases as well as having beveled terminations.
The termination and structure of the questioned specimen show none of these characteristics.

 

[Eu_citzen]

Well, KyleHudson, I guess you have to do a couple of simple tests.

1. Can a knife scratch it? Try on a small spot not open to plain sight. (don't want to ruin the good looks!!)
2. Can vinegar react with it? A small drop will do. Does it bubble and fizzle? (wash of any remaining acid with water!)

DD,
Calcite is trigonal. It does cleave into rhombs. Guess we'll have to limit possibilities.