I have heard of DMD, which is an altcoin. Their site is this:
DIAMOND and this is their
whitepaperNot sure if you are referring to this, but this is just like any other cryptocurrency, like DogeCoins, LiteCOins, Ethereum... basically, alternative currencies to Bitcoin, hence the name altcoins.
The other site bitcoindiamond . org is just a scam site, do not even try.