Milky Quartz

Hardness: 7 on Mohs scale. Color: Opaque white to off-white, sometimes with creamy or brownish tints due to impurities. Luster: Vitreous to greasy. Crystal structure: Trigonal (often massive or anhedral, meaning without distinct crystal faces). Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Milky quartz forms under a wide range of temperatures and pressures within igneous, metamorphic, and sedimentary rocks. It often grows from hydrothermal solutions rich in silica that fill veins and cavities in the Earth's crust, or as a primary component in granitic rocks. The milky appearance is due to microscopic fluid inclusions that scatter light, forming during its growth. Geological age varies greatly depending on the specific deposit, ranging from Precambrian to relatively recent formations.

Milky quartz is a common and abundant mineral with various uses, though less prized than its clearer varieties. It is used as an aggregate in construction materials (concrete, asphalt), in the production of ceramics and glass (especially for silica sand), and as an abrasive. While not typically used in fine jewelry due to its opaque nature, it is sometimes cut into cabochons or beads for costume jewelry or folk art. It is also collected by mineral enthusiasts.

Quartz is the second most abundant mineral in the Earth's continental crust. Milky quartz is often considered the most common type of macrocrystalline quartz. The 'milkiness' that gives it its name is caused by countless minute, trapped water bubbles and gas inclusions. Despite its commonality, well-formed milky quartz crystals can still be aesthetically pleasing to collectors.

Field identification is relatively easy due to its white color, vitreous to greasy luster, hardness (it will scratch glass), and lack of cleavage. It often occurs in massive forms, sometimes with internal fractures. Look for it in veins cutting through other rocks, in pegmatites, or as a component of granitic rocks. It is found globally in virtually all types of geological environments where silica is present. For collectors, it's a good specimen to practice identification skills and understand basic mineral properties.