Ruby and sapphire are simple oxide minerals, należące do układu kryształów trygonalnych, the crystals are mostly hexagonal columnar with glassy luster, przezroczysty do półprzezroczystego, twardość 9, second only to diamond; stable chemical properties, and good toughness and Obvious pleochroism. Although ruby and sapphire have the same chemical composition, they become crystals with different [...]
