Quartz

Hardness: 7 on Mohs scale. Color: Colorless (as in the image), white, purple (amethyst), pink (rose quartz), brown, black, yellow. Luster: Vitreous to sub-vitreous. Crystal Structure: Hexagonal (trigonal). Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

Quartz forms in a wide range of geological environments. It can precipitate from hydrothermal solutions, crystallize from magmas, or form during metamorphic processes. It is also a very common detrital mineral found in sedimentary rocks due to its hardness and resistance to weathering. Geological age varies widely depending on the specific formation event, ranging from ancient Precambrian to relatively recent.

Industry: Used in electronics (oscillators, filters), optics (lenses, prisms), abrasives, and as a component in glass, ceramics, and cement. Jewelry: Many varieties are prized as gemstones (e.g., amethyst, citrine, smoky quartz, rose quartz). Construction: A primary component of sand and sandstone used in building materials. Collecting Value: Widely collected for its aesthetic appeal, crystal habits, and variety of colors.

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is known as rock crystal. The piezoelectric property of quartz allows it to generate an electric charge when mechanically stressed, and conversely, to vibrate at a precise frequency when an electric field is applied, which is crucial for its use in timekeeping devices and electronics.

Identify it in the field by its hardness (scratches glass steel), conchoidal fracture, lack of cleavage, and vitreous luster. It often forms hexagonal prisms with pyramidal terminations. Commonly found worldwide in igneous, metamorphic, and sedimentary rocks. Tips for collectors: Look for clear, well-formed crystals in vugs and veins, or as durable grains in sands and gravels. The specimen pictured is likely a fractured piece of clear quartz, possibly rock crystal.