mineral
Tumbled blue stone and polished red-brown stone
Likely sodalite or blue aventurine; red specimen possibly jasper or polished flint/chert
AI-generated identification · may be incorrectThe left stone is opaque blue-gray with darker mottling and a vitreous-to-waxy luster; likely Mohs 5.5–7. The right is red-brown, fine-grained, and waxy, likely Mohs 6.5–7; exact identification requires testing or a clearer image.
Identified More mineral →
Explore Tumbled blue stone and polished red-brown stone in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
The left stone is opaque blue-gray with darker mottling and a vitreous-to-waxy luster; likely Mohs 5.5–7. The right is red-brown, fine-grained, and waxy, likely Mohs 6.5–7; exact identification requires testing or a clearer image.
Formation & geological history
Sodalite forms in alkaline igneous rocks; aventurine is quartz-rich and metamorphic or hydrothermal. Jasper and chert form from silica-rich sedimentary or volcanic processes, generally from Precambrian to younger ages.
Uses & applications
Used as inexpensive cabochons, beads, tumbled stones, ornaments, and decorative objects; jasper and chert are also used for carvings and occasionally construction aggregate.
Geological facts
The blue stone’s color and texture are consistent with sodalite, but lapis lazuli, dyed quartz, or blue calcite are alternatives. The red stone may be jasper, brecciated jasper, or flint.
Field identification & locations
Check streak, hardness, translucency, and acid reaction: quartz-rich material scratches glass and leaves a white streak; sodalite is softer and typically has a white streak. Common sources include Canada, Brazil, India, and the United States.
