Milky quartz derives its distinctive milky white or cream color from inclusions of gas and liquid bubbles. The degree of milkiness depends on the number and size inclusions present. Crystals are hexagonal prisms with pyramidal ends.
Very large crystals are found in Siberia. Other localities include Brazil, the European Alps, Madagascar, United States and Namibia.
When polished or cut in cabochon, it may be confused with opal.