Yellow Quartz
Quartz var. Citrine · Semi-Precious Gemstone
Crystal System
Trigonal, typically forming as tumbled, massive, or sub-rounded pebble habits due to water-wear
Mineral Group
Silicates (Subgroup: Tectosilicates)
Chemical Formula
SiO2
Formation Process
Hydrothermal veins, pegmatitic pockets, or secondary sedimentary deposits where water-worn pebbles form through alluvial processes
About This Crystal
A small, tumbled, sub-rounded yellowish-brown quartz pebble with a smooth, polished surface texture, translucent to semi-opaque clarity, vitreous-to-waxy luster, and internal cloudy whitish inclusions
Physical Characteristics
Yellow to brownish body color, white streak, conchoidal fracture, distinct lack of cleavage, specific gravity of approximately 2.65, brittle tenacity, and typically inert under UV light
Optical Properties
Singly or weakly doubly refractive with a refractive index of 1.544 to 1.553, low birefringence, and generally no prominent pleochroism in lighter varieties
Hardness & Durability
Origin Region
Global distribution; notable sources include Brazil, Madagascar, and the United States, typically found in alluvial and sedimentary deposits
Hardness & Durability
Mohs hardness of 7, good durability and toughness, highly resistant to scratching, making it exceptionally well-suited for everyday jewelry use
Care & Maintenance
Safe to clean with warm soapy water and soft brushes; avoid harsh chemical cleaners, prolonged direct sunlight to prevent fading, and ultrasonic cleaners if internal fractures are present
Rarity & Value
Common and widely available; value is generally low for tumbled stones, depending primarily on color saturation, clarity, and size, with heat treatment commonly used to enhance pale quartz into vibrant yellow citrine
Special Characteristics
Piezoelectric and pyroelectric properties; internal cloudiness and localized phantom-like white quartz inclusions
Lore & History
Historically used as a talisman for protection against snake venom and evil thoughts, often associated culturally with abundance, prosperity, and the solar plexus chakra in traditional crystal healing lore