Different strokes for different folks... but I prefer to keep a bit of fur from my animal companions. It's sanitary, cheap, and I think it has a small amount of his/her DNA intact- so I feel it's a better rememberance than transformation into a diamond.
If I wanted to memorialize my companion with that much money, I'd donate it to living animals. I think the gem in the picture is beautiful, though.
Peasant (1963-1972) and Fluffy (1970s?-1982- I think of you as 'Ambrose' now)- Your spirits outshone some humans I have known. Be happy forever.