Ruby Dragon [Mystara]

Beyond 120 feet a ruby dragon looks just like a red dragon; closer in, its shimmering scales reveal what it is. It speaks its own tongue, the shared gem dragon language and the language of red dragons.

Its breath is a rolling wave of melting heat that first strikes as a red dragon's fire, growing stronger with age and halved with a save vs. breath weapon. If that save fails, the victim rolls saves vs. magical fire for each nonliving thing in his possession; failures begin to burn or melt. Paper is gone at once, leather in one round, other nonmetal items in two, nonmagical metal in three, and magic items in four or more, plus one round for each plus. Items granting fire immunity or resistance melt too, but take twice as long. Cooling saves an item before it is destroyed, so plunging it in water works, as does magical chill such as ice storm or cone of cold. Partly ruined magic may, at the DM's option, lose a plus or more.

Ruby dragons of any age are wholly immune to fire and heat and love to play in lava and magma. Their tough jeweled hide also guards against cold, giving +1 on saves vs. cold attacks and reducing cold damage by 1 point per die.

It shares the red dragon's favored terrain but is more willing to go up into colder heights and deep below ground.

A greedy carnivore, it also prizes the most precious gems forged in the earth's hottest depths. It gladly attacks dwarves, knowing they hoard the gems it finds so tasty. Anyone cornered by a ruby dragon has a fair chance of buying freedom by offering to guide it to a stash of gems.