While visiting the National Museum of Natural History we saw some pyrite and thought it's geometry would make for great jewelery! We sat down together and modeled this pendant!
NOTE: hole in pendant for chain has a diameter of 3.175 mm (0.123"), which is a little small for the Shapeways chain. You can squeeze the Shapeways loop slightly with pliers, or you could get the below chain from Amazon in the .8mm size (it's what we use with these pendants)
Gold plated:
http://amzn.to/2DIWgvp
White gold plated:
http://amzn.to/2DOFzyD
It's part of a set along with a Pyrite ring we made here:
https://www.shapeways.com/product/MMW8KB2SW/pyrite-ring