Milky quartz

Milky quartz is a milky white, cloudy variety of quartz that ranges from translucent to opaque; it is also known as “white quartz” or “milk quartz”. Chemically it is the same as clear rock crystal (SiO₂). The only difference is the countless fluid and gas bubbles, far too small to see, that were trapped as the crystal grew: they scatter light and make the stone look white. It is very plentiful in nature and is found mostly as veins cutting through rocks.

Industry: according to Ankara University course notes it is rarely used as an ornamental stone, but it is widely used in making ceramics and porcelain. Pure vein quartz from Russia's Polar Urals is considered for growing single crystals and melting glass. Decoration and jewellery: it is used in carvings, beads, countertops and decorative tiles. Prospecting: gold prospectors follow milky white quartz veins, because gold is so often found with them. Collecting: well-formed crystals and pieces showing gold have a place in collections.

It has a hardness of 7 on the Mohs scale. It scratches glass and steel; a steel knife cannot scratch it. Its specific gravity is 2.65–2.66 g/cm³.

Its best-known localities: Ouachita Mountains, Arkansas and Oklahoma, USA; Mother Lode, Sierra Nevada, California, USA; Subpolar and Polar Urals, Russia; Příbram, Central Bohemia, Czech Republic.

It is milky white or cloudy white; little light passes through it, and you cannot see through it. Its lustre is glassy, but the bubbles inside sometimes give it a slightly greasy sheen. It is hard (7): it scratches glass, and a steel knife cannot scratch it. This sets it apart from white calcite and marble, which a knife scratches easily.

On the “street to diamond” value ladder it sits on step 3 of nine: Building and industrial stone. Because milky quartz is so plentiful, it is worth less than other varieties of quartz. Its value comes mostly from its purity as an industrial raw material: it is used in making ceramics and porcelain, and high-purity vein quartz is used to grow single crystals and to melt glass. As an ornamental stone, an even white colour, freedom from cracks and a good polish matter. Well-formed crystals and pieces with visible gold are more sought after by collectors.

Crystal-therapy sources present milky quartz (“snow quartz”) as a stone of spiritual cleansing and claim that it supports the immune system. Some of the same sources believe that the stone helps new mothers produce milk. Some crystal-therapy websites claim that milky quartz boosts self-confidence, sharpens the mind and helps meditation. There is no scientific evidence that milky quartz supports immunity, increases milk supply or boosts self-confidence; its white colour comes only from microscopic bubbles that scatter light. Breastfeeding problems call for a doctor or midwife, and immune problems for a doctor. This section reports beliefs; it is not health information. There is no scientific evidence for these claims and no stone replaces medical treatment.