mineral

Yellow Agate

Silicon Dioxide (SiO2)

Hardness (Mohs): 6.5-7; Color: Yellow, cream, amber, and translucent white; Luster: Waxy to vitreous; Crystal Structure: Trigonal (Microcrystalline); Cleavage: None; Specific Gravity: 2.6

Color: Yellow, cream, amber, and translucent white
Luster: Waxy to vitreous

Identified May 28, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness (Mohs): 6.5-7; Color: Yellow, cream, amber, and translucent white; Luster: Waxy to vitreous; Crystal Structure: Trigonal (Microcrystalline); Cleavage: None; Specific Gravity: 2.6

Formation & geological history

Formed in volcanic or sedimentary rocks as silica-rich groundwater fills cavities, slowly precipitating out layers of microcrystalline quartz or chalcedony. This specimen specifically looks like a river-tumbled or water-worn chalcedony/agate pebble.

Uses & applications

Used in gemstone carvings, jewelry (pendants, beads), decorative tumbled stones, and as a collector's specimen.

Geological facts

Agate is a variety of chalcedony characterized by its translucency and delicate banding. The yellow hue is typically caused by inclusions of iron oxides such as geothite or limonite.

Field identification & locations

Identify by its waxy luster, translucency when held to a light source, and lack of visible crystalline structure compared to quartz. Common in gravel pits, riverbeds, and beach deposits across the globe.