Source
dripdri•

I think it might be opal too. Something about that fracturing and the way it takes light. Is that light brown patch host rock/mud, or is that the center of a geode sort of formation?

1
absteeleOP•

It's got a decent amount of silt and what I think is calcite caked on in some spots, and then a bunch of different shades of opal, plus some areas that seem more like chalcedony. I found a couple other pieces that are more intact and seem like they might be limb casts, and then a few chunks with darker, cylindrical structures inside that look a lot like small limbs or knots or something. Can't wait to see how they all clean up.

1
theonetheonlytc•

Looks like common opal to me. The waxy luster shown on the white and reddish part looks just like it to my eyes.

1
MineralPirate•

From saddle mtn it's opalized wood. The iridescence is a thin film of trapped oil. It's a bit lighter then agatized wood but breaks like obsidian, extremely sharp.

I have a ton of this stuff from all over that area.

1
absteeleOP•

Yeah, I nicked my finger on a piece yesterday! That makes sense about the thin film oil - the iridescent colors were reminiscent of oil that draws up from fresh asphalt after the rain.

Any advice on the best way to clean & prep pieces? And how well does the opal take a polish? It seems kind of brittle, like it would shatter in a trim saw. But soft enough that I might be able to hand-polish.

1