Citrine
Quartz var. Citrine · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal; hexagonal prisms terminated by rhombohedra. Habit is commonly massive or druzy clusters.
Mineral Group
Silicates (Subgroup: Tectosilicate)
Chemical Formula
SiO2 (Silicon Dioxide with trace amounts of Ferric Iron)
Formation Process
Magmatic or Hydrothermal. Forms as a primary mineral in igneous rocks like granites or by secondary processes where amethyst is heated naturally or artificially.
About This Crystal
Transparent to translucent yellow-to-brownish crystal. The image shows a cluster of golden-yellow crystals with a vitreous to waxy luster, displaying some internal fracturing and uneven surface texture.
Physical Characteristics
Color: Yellow to honey-orange; Streak: White; Cleavage: None; Fracture: Conchoidal; Specific Gravity: 2.65; Fluorescence: Usually inert.
Optical Properties
Refractive Index: 1.544-1.553; Birefringence: 0.009 (uniaxial positive); Pleochroism: Weak in natural specimens; Phenomenon: None (rarely chatoyant).
Hardness & Durability
Origin Region
Brazil (primary), Madagascar, Russia, and Spain. Often found in pegmatites and hydrothermal veins.
Hardness & Durability
Mohs Hardness: 7; Toughness: Good; Stability: Stable to light, but high heat can cause color change or fading.
Care & Maintenance
Clean with warm soapy water and a soft brush. Avoid ultrasonic or steam cleaners if there are many inclusions. Keep away from prolonged direct sunlight.
Rarity & Value
Relatively common in its heat-treated form (amethyst-to-citrine); naturally occurring citrine is quite rare and fetches a higher price based on saturation.
Special Characteristics
May contain 'phantom' growth layers or inclusions of other minerals. Heat-treated varieties often show white, opaque bases.
Lore & History
Historically known as the 'Merchant's Stone' for its association with prosperity. Ancient Greeks used it as a decorative gem as early as the Hellenistic Age.