Yellow Chalcedony (Agate)

Physical Properties

Hardness: 6.5-7 (Mohs), Color: Translucent yellow to honey-orange, Luster: Vitreous to waxy, Crystal Structure: Trigonal (microcrystalline/cryptocrystalline quartz), Cleavage: None, Specific Gravity: 2.60-2.65

Formation & Geological History

Formed in cavities of volcanic rocks or sedimentary environments through the deposition of silica-rich groundwater. Age ranges from recently formed to millions of years old.

Uses & Applications

Used primarily in lapidary arts, jewelry (cabochons, beads), and as a decorative or metaphysical stone in crystal collections.

Geological Facts

Yellow chalcedony is part of the quartz family. When it shows banding, it is technically an agate; without banding, it is simply chalcedony. It has been used for seals and amulets since ancient times.

Field Identification & Locations

Identify by its waxy luster, hardness (it will scratch glass), and lack of visible crystal grains. Often found as river-worn pebbles or within geodes in volcanic regions globally.

Identified on: 5/7/2026

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