Yellow Quartz / Quartz Pebble
Quartz var. Citrine / Quartz · Semi-Precious Gemstone and Mineral Specimen
Crystal System
Trigonal, commonly found as water-worn pebbles or massive aggregates in sedimentary contexts.
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2
Formation Process
Formed through mechanical weathering, transportation, and deposition of primary quartz from igneous or metamorphic rocks into sedimentary environments.
About This Crystal
A small, water-worn, tumbled pebble exhibiting a smooth, rounded surface with a yellowish-brown to brownish-gray coloration, translucent to semi-translucent transparency, and a waxy to vitreous luster typical of weathered quartz.
Physical Characteristics
Color ranges from brownish-yellow to light gray; streak is white; cleavage is absent; fracture is distinctly conchoidal; specific gravity is approximately 2.65; tenacity is brittle; exhibits piezoelectric properties.
Optical Properties
Uniaxial positive with a refractive index of 1.544 to 1.553; birefringence is 0.009; singly refractive in certain orientations but optically active; typically lacks strong pleochroism in this color variety.
Hardness & Durability
Origin Region
Global distribution; commonly found in riverbeds, alluvial deposits, and beaches worldwide.
Hardness & Durability
Mohs hardness of 7; good toughness and excellent chemical stability; highly durable and suitable for all types of jewelry use due to the absence of cleavage.
Care & Maintenance
Can be cleaned safely using warm soapy water, ultrasonic cleaners, and soft brushes; resistant to most household chemicals; stable in sunlight, though heat treatment can alter color.
Rarity & Value
Common; widely available globally with low commercial value for tumbled pebbles, though high-grade natural specimens can command higher prices.
Special Characteristics
Displays natural water-wear smoothing (alluvial rounding); may exhibit weak triboluminescence or piezoelectricity under stress.
Lore & History
Historically used across various cultures for amulets and polished stones; in modern crystal healing, quartz varieties are traditionally associated with clarity, energy amplification, and the solar plexus chakra, though these remain traditional beliefs rather than scientific claims.