mineral

Yellow Quartz (Chalcedony or Agate)

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale; Color: Translucent honey-yellow to pale gold; Luster: Vitreous to waxy; Crystal Structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Translucent honey-yellow to pale gold
Luster: Vitreous to waxy

Identified March 22, 2026More mineral →

Explore Yellow Quartz (Chalcedony or Agate) in the encyclopedia →

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Physical properties

Formation & geological history

Formed from silica-rich hydrothermal fluids cooling in rock cavities or veins. This specimen likely weathered into a rounded river pebble over thousands of years. Common in volcanic regions and sedimentary deposits.

Uses & applications

Used widely in lapidary work, jewelry (tumbled stones, beads), and as a collector's specimen. High-purity quartz is also used in electronics and glass manufacturing.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. When microcrystalline and translucent like this, it is often referred to as Chalcedony; if it shows banding, it is called Agate.

Field identification & locations

Identify in the field by its translucency (light passes through it), its ability to scratch glass, and its smooth, water-worn texture if found near coasts or rivers. Commonly found on beaches in the Pacific Northwest and UK.