Zircon is a lustrous gemstone that comes in colors ranging from golden brown to
red to violet to blue. Pure zircon is colorless, but most zircon stones are brown.
Zircon stones can be heat-treated to become blue or colorless. Clear zircon is
sometimes sold (intentionally or otherwise) as diamond.
Zoisite is opaque grayish or whitish mineral with green or black streaks occurring
in rhombohedral crystals or columnar masses.