I've been working, much more successfully than the cracked lentil, with Chalcedony glass. I have mostly used stringers I pulled from glass I purchased from Gaffer Glass USA and shards that I purchased from Knattydreadz on Etsy. It doesn't seem to matter. The results are spectacular and easy to achieve. Take a look. If I can do it, anyone can.
I used bases of black, cobalt blue, medium red, and orange. These beads were made using shards and stringers. That reduces the possibility of incompatibility cracks. I am simply overwhelmed by the beauty of this glass! It's amazing! Here's another shot from a different angle.
There's not a bad one or a fugly one in the bunch. Amazing!