Chemical composition -- Manganese carbonate with iron and
calcium.
Color -- Pink to red.
Optics -- R.I. 1.58-1.84. Uniaxial negative.
Durability -- Hardness 3.5-4.
Crystal structure -- Hexagonal.
Specific Gravity -- 3.4-3.6.
Sources -- Colorado, South Africa, Argentina, Peru. Usually massive piece suitable for cabochons and carvings, but small, rare crystals have been faceted. Some of these are spectacular in appearance, but they are difficult to cut due to perfect cleavage and too fragile for use in jewelry.