Quartz

Hardness: 7 (Mohs scale), Color: Colorless, white, purple (amethyst), pink (rose quartz), brown (smoky quartz), yellow (citrine), Luster: Vitreous (glassy), Crystal Structure: Hexagonal (trigonal), Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Quartz forms in a wide variety of geological environments. It can crystallize directly from magma in igneous rocks like granite, precipitate from hydrothermal fluids in veins, or form in sedimentary rocks like sandstone and chert. Its geological age varies widely depending on the specific formation event.

Industry: Dominant in electronics (oscillators, filters), optics, and abrasives. Construction: Used in concrete, mortar, and as a gemstone grit. Jewelry: Many varieties (amethyst, citrine, rose quartz, smoky quartz) are popular gemstones. Collecting: Valued for crystal formations and aesthetic appeal.

Quartz is the second most abundant mineral in Earth's continental crust. Its piezoelectric property (generating an electric charge under mechanical stress) makes it crucial in electronics. The largest clear quartz crystal ever found was in Brazil, weighing over 44 tons.

Field Identification: Look for its characteristic hexagonal prismatic crystals, vitreous luster, and hardness (scratches glass). Common Locations: Found globally in various rock types, including igneous, metamorphic, and sedimentary. Very common in pegmatites, hydrothermal veins, and sandstones. Tips for Collectors: Look for well-formed crystals in vugs or geodes. Different color varieties are often found in specific regions.