I was attending one of the traveling bead shows over the weekend and came across a booth (EarthArt) selling all sorts of mineral specimens and geodes. They had the coolest thing where you could pick a rock from various bins and the guy running the booth would load it into a vice-like contraption. He would then give it a couple clicks with a socket wrench and the rock would crack. (You can see the crack above if you look closely.) Once cracked, it was carefully handed back to its purchaser to be opened to reveal the jewels inside.
It was very exciting and I got a bit carried away with it. When I took the two home that I purchased on Saturday for $5 each and shared the calcite, smoky quartz and amethyst with my husband, he asked me to get a couple of the $10 ones on Sunday. No problem! They are just so cool. I have no idea what I'll do with them, but I got some nice ones!
This is one of the Los Choyas ones. It contains chalcedony and smoky quartz (if I remember correctly).