How and where do double-terminated crystals form?

Question

How and where do double-terminated crystals form? Most terminated crystals form by 'growing' out of a rock. Which causes one side to be flat,(or whatever the shape of the rock it 'grew' out of was shaped like), and the other side to be 'terminated'. Meaning that the one side has a natural faceted end. Double-terminated crystals obviously couldn't form like this.

Answer 1

Double-terminated crystals are crystals with natural faces on both ends. They form in free-floating pockets of liquid that evaporate slowly, leaving perfectly formed crystals with two terminations. These crystals are usually found in sedimentary rock from subterranean marine deposits that were laid down through geologic history.