sedimentary

River Stone (Chalcedony/Jasper variety)

Microcrystalline Quartz (SiO2)

Hardness: 6.5-7 on Mohs scale; Color: Tan, brown, gray, and cream with slight translucency; Luster: Waxy to vitreous; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.6-2.65.

Hardness: 6
Color: Tan, brown, gray, and cream with slight translucency
Luster: Waxy to vitreous

Identified May 29, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed via the precipitation of silica from groundwater in the cavities of sedimentary or igneous rocks. This specific specimen has been chemically and mechanically weathered and rounded through transport in a fluvial (river) environment over thousands of years.

Uses & applications

Used primarily for landscaping, decorative gravel, aquarium substrate, and sometimes as pocket stones or for rock tumbling hobbies.

Geological facts

The smooth, rounded shape is a result of years of abrasion against other rocks in a riverbed. These stones are the most common entry point for amateur rock hounds due to their polished appearance and ease of discovery.

Field identification & locations

Identified by its smooth, water-worn texture and hardness (it can scratch glass). Commonly found in current or ancient riverbeds and along beaches. Collectors should look for unique banding or internal patterns.

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