It's been with me for as long as I have been around, so it's approximately...

[He trails off, thinking for a few seconds.]

Probably about a millennium and a half. It is my core, my life essence. I suppose the heart might be a similar analogue for humans. It is tradition for my kind to cut our representative stone and set it as a sort of coming-of-age rite. It's a simple square cut set in silver. It's not my best work, really.

[He maintains a genial smile as he speaks.]