Diamond type
Diamond type is a method of scientifically classifying diamonds by the level and type of their chemical impurities. Diamonds are separated into four types: Type Ia, Type Ib, Type IIa, and Type IIb. The impurities measured are at the atomic level within the crystal lattice of carbon atoms and so, unlike inclusions, require an infrared spectrometer to detect.
Metallic dragon
Metallic dragon is a classification of dragon found in the role playing game "Dungeons & Dragons". In this setting metallic dragons are of good alignment. Bahamut is the deity of good-aligned dragons and metallic dragons, and currently the only known Platinum dragon in existence. Metallic dragons have played a large role in D&D's various monster compilation books, and for most of the game's history five main types - brass, copper, bronze, silver, and gold - were presented as roughly analogous to the five types of chromatic dragons. The fourth edition of the game's second "Monster Manual" substituted iron and adamantine dragons for brass and bronze, and released the latter dragons in a later book alongside cobalt, mercury, mithral, orium, and steel dragons.