What kind of crystal is this?

[catfishjim90]

Got this at a flee market, waighs about 15 pounds. Thanks for any info. Here is on other pic of the crystal View attachment 1522112

 

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[Jim in Idaho]

Looks like glass.
Jim

 

[DDancer]

Thanks for adding the second picture. Not sure but it looks like florite however I've not seen inclusions, the white crystaline spots, in florite like that. About how hard is the crystal, test it in an inconspicuous spot as it is a good looking cluster.

 

[loco oro]

I agree with ddancer, looks like fluorite, cubic habit, hit it with a UV light, should fluorece if so, nice big cabinet piece, I like it

 

[Clay Diggins]

It's not Fluorite with that cleavage. Flourite has perfect cleavage and a splintery sub-conchoidal fracture.

I'm with Jim. I'd guess glass from the pictures. Possibly from a building fire.

 

[Eu_citzen]

I'm also inclined to think glass.

 

[stdenis_jd]

I'd use a cheap iron nail to do a scratch test - you don't want to use a good one that is hardened steel...if it scratches the green, it could be flurite (COULD) - if it doesn't scratch it then use a "good" nail. Either way it's probably glass.

 

[IAMZIM]

I agree with Clay diggings, all the fluorite I have cleaves into octohedrons (spelling sucks sorry). The concoidal fracturing looks an awful lot like glass to me.

 

[DDancer]

I agree thats what the fracture patten suggests, glass, however I tossed fluorite out due to what appears to be structured crystal along those lines. Sometimes nature gets weird with things and those, I'll call them snow flakes, inclusions as well as what appears to be a base rock give me pause. It is possible it is melt glass that may have some how been formed by debris in a fire but its just weird to me.

 

[Eu_citzen]

I agree thats what the fracture patten suggests, glass, however I tossed fluorite out due to what appears to be structured crystal along those lines. Sometimes nature gets weird with things and those, I'll call them snow flakes, inclusions as well as what appears to be a base rock give me pause. It is possible it is melt glass that may have some how been formed by debris in a fire but its just weird to me.

Probably the inner most (brick) portion of a glassmelting oven.
I've tore a few of those down, the inner-most bricks can begin to turn to glass from the heat, giving a crystalline-like appearance.