Recently obtained these in a bundle. It’s sort of like a sage green and grey colour. Grey varies from light to dark. Is anyone familiar with this material? TIA 
This is a guess, as I haven’t seen stones exactly like that, but it may be a type of obsidian. Any chance it’s from Australia or New Zealand? I have a bunch of “snowflake” obsidian from that region (at least that’s what it’s officially called, i’m not sure i agree it’s obsidian, tho). the color/mineral patterns are different but the colors of the blacks and grays are nearly identical, and when polished, the surface looks the same. You could possible measure specific gravity and that may help to support or eliminate this as a possibly. They are cool looking, that’s for sure. Any chance there are small (tiny, about 2mm or less) notches anywhere on these? Also, are there splotches of a plaster like calcite anywhere? Just curious.
A lot of opal comes from that region, some of which (Koroit, Boulder, etc) appears “in matrix” which may explain the purple. Again, I’m just guessing.
Maybe pet. Wood
I’d guess Gneiss
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looks like a rock and not a mineral… not obsidian as the banding is not parallel… gneiss or quartzite with chlorite or another mafic mineral is my guess. what ever it is it’s not precious.