Grandparents Platinum Wedding Band

by Emily
(Perth, Western Australia)

Hi there,
My mum recently gave me my nanna's jewellery box and in the contents was a plain platinum ring. I asked my mum if it was nanna's or pop's and she said she didn't know, but she thought that she heard that one of them had a cheap wedding band replaced and that this might be the cheaper one.

I thought nothing of it, but being the sentimentalist I am, I would like to wear it for my own wedding band in 18 days time. It is therefore important to me to find out it's origins - if it couldn't possibly have been either of theirs then I won't wear it.
It is plain, silver-colour, quite heavy (which is what made me look closely at it). Inside is stamped:
K&D
PLATINUM
There is no other marking. I expect that this is not a valuable ring, however I'm interested in the K&D and what it means...
Thanks, Emily