FMF - Friends of Minerals Forum, discussion and message board

[LoveAlwaysBlake]

Hey everyone.

I found this rock in the yard. I live on a bluff next to the Wabash River so mostly a limestone area. I started shining it up and realized I wasn't really sure what it was. I've Googled all I can but maybe someone here has seen something similar? It has red/gold pieces on the outside and inside. Also metallic spots throughout some gold some silver in color which made me think pyrite as I also spotted some Black crystal? I don't know if its visible but inside is broken into small rectangular sections. Its just weird to me. Scratch test was a 7 so quartz maybe? New to this so again any help appreciated.

[Bob Harman]

Looks like water worn calcite with long gone chips of other included "stuff" that has eroded out.

Put your specimen in household vinegar for several minutes and it should fizz. BOB

[LoveAlwaysBlake]

Thank you Bob. That makes so much sense now that I think about it!

[Peter Perkins]

Bob and LAB - do you think it might be Quartz with Tourmaline in it? I wouldn't expect calcite to be quite so shiny and, if calcite, I would expect a pebble to show at least some evidence of damage from its journey (river or shore-line) and for there to be some Rhombic cleavage showing.

[Bob Carnein]

I'm with Peter on this, though I'm not sure about the tourmaline--I think it's more likely quartz with some K-feldspar and maybe biotite mica. Wisconsin ice extended more that half-way south through Indiana, including the central Wabash valley. I'm familiar with glacial deposits in Ohio, and it wouldn't be at all unusual to see something like this there. However, a rounded calcite fragment would definitely be odd.

[James Catmur]

Look in my backyard and you would find magnetite from Malaysia, blue john from Derbyshire, obsidian from Mexico, smithsonite from Spain, etc.

Plus all the waste from a collection I was given with no labels.

So backyard rocks can come from all over the world.

[LoveAlwaysBlake]

[LoveAlwaysBlake]

[LoveAlwaysBlake]

Here's a picture where you can sort of see the lines inside and the crystal bits.

[Volkmar Stingl]

Looks like a pebble of sheared quartz.

[James Catmur]

I tend to agree, given the hardness and photos