mineral

Red Agate (Carnelian)

Chalcedony (SiO2) with iron oxide inclusions

Hardness: 6.5-7 (Mohs); Color: Red, orange, or brownish-red; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.64

Hardness: 6
Color: Red, orange, or brownish-red
Luster: Vitreous to waxy

Identified March 18, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: Red, orange, or brownish-red; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.64

Formation & geological history

Formed in volcanic rocks (lavas) where silica-rich groundwater fills gas bubbles (vesicles), transitioning through various phases into microcrystalline quartz; frequently found in Cenozoic era volcanic regions.

Uses & applications

Commonly used in jewelry (cabochons, beads), decorative carvings, and as tumbled stones for metaphysical collecting.

Geological facts

Ancient Romans used carnelian for signet rings because hot wax does not stick to the stone; it is mentioned in Egyptian mythology as a source of renewed vitality.

Field identification & locations

Identify in the field by its semi-translucency when held to light and its smooth, waxy texture. Frequently found in riverbeds or gravel pits in states like Oregon, Washington, and regions of Brazil and India.

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