When I went to Florida a couple of weeks ago, and I didn't find any particularly spectacular shells but it occurred to me that a lot of little cute ones would make a nice necklace, so I set myself the task of making one.
The initial design. I swapped the order of the very tiny and the second from the outside large shells for increased symmetry and gave up on the black shells on the right side; they're simply too thick. I can't even get a dent in them. They've been replaced with white/orange shells which are more cohesive color-wise if a little too large.
The small shells are mostly chosen for their beautiful purple interiors. They won't be visible worn, but I'll know how purple they are :)
I did some google searching, and it turns out that seashells are notorious for being difficult to work with. Luckily, I had plenty of extras to practice on. I've only broken two so far though, so! (and had suitable replacements for those!)
I took a pin with a broad head and a panelling nail and started off by digging the nail into a suitable spot on the inside of the shell. Working from the inside makes sense because then you can support the outside of the shell (the convex side) with your fingers, spreading out all the pressure to prevent fracture. Once a dent had been made in the shell, I would switch over to the pin and basically just bear down on that until I could hear the shell begin to break. The pin makes a hole about 1/30" in diameter. Some of the shells had holes already in them, and those are about 3/60".
The only one I broke (my dad broke the other trying to use a drill on it) was because I had just been trying to puncture a particularly thick one (which was why my dad tried to drill it), and forgot how little force was necessary on the smaller ones.
I would estimate it takes about 15 minutes for the more difficult ones, and as little as one minute for the easy ones. Some of the mother-of-pearl looking pieces were very easy to pierce.
I haven't quite decided how to arrange them on a necklace, but my plan right now is to make little clasps out of copper wire and then tie those to fishing line. I might switch to an all-copper get up though. originally, I was going to use all fishing line, but the copper was too tempting <3( picccccctures~ )
I hope it turns out well! I've been afraid to start working on it the last two weeks, and it took the looming hulk of a test tomorrow to get me eager enough to procrastinate to just start.