mineral

Raw Agate (Rough Agate Nodule)

SiO2 (Microcrystalline Quartz / Chalcedony)

AI-generated identification · may be incorrect

Mohs hardness: 6.5 - 7; Color: reddish-brown, tan, orange-red, and translucent white patches; Luster: waxy to vitreous; Crystal Structure: Trigonal/Microcrystalline; Cleavage: none (conchoidal fracture); Specific Gravity: ~2.58 - 2.64

Hardness: 6
Luster: waxy to vitreous

Identified July 26, 2026More mineral →

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Physical properties

Formation & geological history

Formed in cavities within volcanic basaltic or metamorphic rocks where silica-rich groundwater deposited successive layers of chalcedony over extended periods. Often eroded out of host rock and rounded by stream or glacial action.

Uses & applications

Popular among rockhounding hobbyists for lapidary work, tumbling, cutting into cabochons, slabbing, and ornamental carving. Used in jewelry making when polished.

Geological facts

The pitted, rough surface with waxy spots and translucent rind is typical of rough agates found in riverbeds and gravel pits, such as Lake Superior agates or Carnelian agates. Cutting or tumbling reveals vibrant internal banding.

Field identification & locations

Look for a characteristic waxy or greasy texture, translucent edges when backlit, pitted orange-red exterior skin (peel), and lack of cleavage. Commonly found along riverbanks, gravel bars, and volcanic terrains worldwide.