They now can take a pet's or person's ashes and make gemstones out of them, and put them in jewelry. There's also this one artist who incorporates ashes into paintings. I think the former is nicer than the latter. Be weird trying to insure a necklace, etc. though--"Can you put a higher value on this? These gems are actually my grandparents here, mom and dad are here, and here's Fluffy, Rover and Tweety. So this has more than just sentimental value, at least the usual kind."
Or if you really want to make an impression on someone, when somebody asks you what kind of gems you're wearing, you point to each and say, "Well, right here is Grandpa Smith, here's Grandma Smith, those two here are Grandma and Grandpa Jones, these two are Mom and Dad, here's my kitty Fluffy, my dog Rover, and parakeet Tweety, and I'm saving this spot here for my husband, and this one for me, when it's my time. My kids will be inheriting their whole family!"
