Throbert, your knowledge about Arabic sounds very good(while you say you know zero about Arabic)
But i just wanna add a tiny little thing; that the main word "Adamas" was from Greek orgin, Then it came to "Farsi/Persian" with a new form --> "Mas"
And Then it went from Farsi/Persian to Arabic with this form --> "Almas"
However we use 'Almas' mainly in Farsi nowadays, too.