gemstone

Polished carnelian (likely brecciated agate) heart

Microcrystalline quartz, SiO₂; chalcedony with iron-oxide coloration

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; translucent reddish-orange to brown with gray/cream inclusions, waxy to vitreous luster, cryptocrystalline quartz, and no visible cleavage. The smooth heart shape is human-cut and polished.

Identified August 25, 2026More gemstone →

Explore Polished carnelian (likely brecciated agate) heart in the encyclopedia →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities or fractures, with iron oxides producing red-orange colors; brecciation and later cementation create contrasting patches. Chalcedony deposits range from Paleozoic to Cenozoic, depending on locality.

Uses & applications

Used for cabochons, carvings, beads, hearts, and ornamental objects; durable but less valuable than transparent quartz gemstones.

Geological facts

Carnelian is the red-orange variety of chalcedony, while agate is banded or patterned chalcedony; this specimen appears to combine both descriptions.

Field identification & locations

Identify by its fine-grained waxy appearance, reddish iron staining, lack of cleavage, and ability to scratch glass. Common sources include India, Brazil, Uruguay, Madagascar, and the United States.