On our recent trip digging for Herkimer Diamonds, I also picked up and kept chunks of calcite. I didn’t know what it was until someone told me. I am still learning all this stuff. But it looked interesting, and some of it was hard to tell from the diamonds (quartz) while it was dirty/muddy anyway. It was just easier to throw it in the bag.
But now that we are home, I have been cleaning up all the stuff we found. I am actually surprised at how many small chunks of calcite that we collected. Most are small, but a few pieces are larger with small pieces of rock attached.
I was reading stuff on the web and I found some stuff talking about the calcite. From what I understand, the calcite is one of the last things to form, and can form around the quartz crystals. So some of my small hunks of calcite might have Herkimer diamonds inside them. I know for sure a couple pieces do since the crystal is partially exposed.
But something else I learned was that the calcite can be disolved by soaking it in white vinegar.
So I took a few of the chunks of calcite with exposed quartz crystals, and set them in a bowl with distilled white vinegar. Right away, tiny bubbles started coming off the calcite. I kept checking back and I could see the quartz crystals becoming more and more exposed as the calcite was slowly eaten away. I placed some more pieces of calcite in the vinegar that may or may not have Herkimer diamonds in them. When I got up the this morning, the chunks were smaller. The bubbling action seemed to have stopped, so I replaced the used vinegar with some fresh vinegar.

Posted by Rob in Rockhounding on April 25th, 2008 | 8 Comments