Those are implosion pendants.
Get a fat rod of clear 10-14mm.
Heat up a blob on the end and gently flatten, so it looks like a chubby disk.
Draw on the disk (the same side you just smooshed) dots... lines... petals... what ever.
Gently melt them in heating only the RIM of the maria (disk)
occasionally gently push the maria back into a disk... the lines/dots will start to move inward toward what will be the lens.
If you want the black background like in your picture, add a black blob and squish into place AFTER you get your design pushed it where you want it.
After you have your design pushed in as far as you want, you need to punty (clear glass rod 5-6mm) to the disk, so you can remove the bigger rod and create your lens. A punty is just a fancy name for a holder.
melt off the large rod near the rim of the disk.
shape/ form the lens... I use gravity and the natural flow of the glass, but you can also use molds/shapers.
now you need to punty up again to the END of the disk, so you can pull your loop.
see that little point on the end of your picture? Put a punty there.
break off your first punty... you won't need it any more.
start to heat the end of the disk OPPOSITE of your newest punty. when it SOFTENS (not melty or blobby) you can pull out/stretch a piece of the glass using yet another punty.
Then I use a round nose pliers to put the pulled bail where I want it... and attach it to the back of the pendant.
After the loop is formed, let it set up, grab it with your pliers, break off your punty, fire polish and toss it in the kiln.