THE STARS ARE RIGHT!!
Read some years ago some Russian researchers workngon carbon 60, made carbon60 diamonds...what they didn't expect was for it to be *magnetic*
ultimate space craft skin, or perhaps, ICBM body, so that research kind of seems to have disappeared...
point being, it had a melting point of 1200C, was not only hardest substance known (harder than normal diamonds) it's TOUGHER than about anything else known, too (it's C60), plus since it's magnetic it would form a magnetosphere and keep out charged particles (essential for spacecraft and a major problem at present).
Also conducts electricity.
now, imagine that as a D&D weapon/armour material!
Oh and DeBers keeps a stockpile of 10,000 TONS of diamonds: diamonds below 4 carats or un-coloured, or without a star aren't worth much, in reality. Big con game.
Rubies some emeralds now they
are rare.
best though is opals as, far as I am aware, it's still impossible to manufacture them and DAMN are they gorgeous.
Only ever seen one diamond that looked good, 4 carat almost square, antique. had a fire that literally hurt the eyes.
