A couple of people were curious about geodes. They're are crystalline, and form in cavities underground. The crystals form on the inside walls of the cavities, and grow inwards. Many geodes you see (do a Google search) are hollow and lined with beautiful crystals. Sometimes the crystals have grown to fill up the cavity, and the geode is solid. If this kind has layers of vivid colors, they'll cut them into thin slabs and sell them. I'm sure mine don't have pretty colors, and only a couple are hollow.

Here are two of mine. The smaller one is oblong, and seven inches across at the widest. The larger one is nine or ten inches around. Ranunculus's is probably seven inches, but more spherical.
Here are two of mine. The smaller one is oblong, and seven inches across at the widest. The larger one is nine or ten inches around. Ranunculus's is probably seven inches, but more spherical.
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Date: 2009-01-26 12:38 am (UTC)From:I can't say I have any that are spectacular.. mine are all three inches are smaller.. but they are "cracked" to show thin inside.
Most are quartz only, but I do have one that has both quartz and amethyst crystals inside.
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Date: 2009-01-26 02:01 am (UTC)From:no subject
Date: 2009-01-26 03:23 am (UTC)From::)
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Date: 2009-01-29 03:24 pm (UTC)From:I would be. You need a rock slicer!
:D
And you just found these in your yard?
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Date: 2009-01-29 06:23 pm (UTC)From:I suspect they're rather dull, off-white, smooth crystalline stone. Maybe I'll cut open one of the smaller ones. But I know that a couple of mine are hollow. I'm more curious about them. I guess I'm a litle afraid to damage them.