Yellow Quartz (Citrine or Yellow Chalcedony)
Silicon Dioxide (SiO2)
Rock Type: mineral

Physical Properties
Hardness: 7 (Mohs scale), Color: Pale yellow to honey gold, Luster: Vitreous to waxy, Crystal Structure: Trigonal/Hexagonal, Cleavage: None (Conchoidal fracture), Specific Gravity: 2.65
Formation & Geological History
Forms in igneous rocks like pegmatites or hydrothermal veins; can also be found as water-worn pebbles in sedimentary deposits. Naturally yellow quartz (Citrine) is often the result of iron impurities or natural irradiation over millions of years.
Uses & Applications
Predominantly used in jewelry, as decorative gemstones, and in crystal healing practices. Industrially, quartz is used in glassmaking and electronics, though yellow varieties are primarily ornamental.
Geological Facts
Natural citrine is quite rare; most commercial 'citrine' is actually heat-treated amethyst or smoky quartz. The color is caused by trace amounts of aluminum or iron.
Field Identification & Locations
Identify by its hardness (will scratch glass) and lack of cleavage. Look for the 'waxy' appearance typical of tumbled or river-worn quartz. Found globally, with notable deposits in Brazil, Madagascar, and Russia.
Identified on: 5/20/2026
Mode: Standard