It's a cut-coin pendant. I got the idea from a jeweller in Ironbridge who specialises in the technique (though I have since learned that there are many others around the world doing similar work). As you might guess, it was for a relative whose first initial is 'L' and was born in 1999 (a century after the coin was minted). It's 16mm in diameter, which is smaller than a modern five-pence piece (incidentally there was an even smaller silver 1.5 pence coin but they are pretty rare). Here's a photo of the coin before I started work on it:
It's an 1899 British silver threepence. Because it was minted before 1920 it's made from sterling silver, which is 92.5% silver, 7.5% copper (the alloy makes it a bit harder-wearing than pure silver would be). I also made the attachment rings from sterling silver wire and soldered them on with silver-solder, and supplied it with a fine sterling silver chain (not made by me).
I cut it out by hand using very small diameter drill bits, a jeweller's piercing saw with a ridiculously fine blade, and a pair of Optivisor magnifying glasses. I couldn't have done the work without decent magnification - often I would spend a few minutes obsessing over a particular detail, then flip the visor up and look at the work I'd just done, only to find that I could barely see the feature with my naked eyes. It's slightly frustrating to look at a photo of the finished coin taken with my macro camera setup because it shows up flaws that you just can't see without magnification. I think I definitely got better at following the lines accurately after a few hours' practice. In hindsight I over-polished parts of it, particularly the crown, removing some of the fine details. But for a first attempt I'm quite pleased with it!
Incidentally, Christmas is coming up: if any of you are interested in commissioning me to make something similar, please drop me a line to discuss the details.