sedimentary

Black Mountain Stone (Seiryu Stone)

Limestone with Calcite veins (CaCO3)

AI-generated identification · may be incorrect

Hardness: 3-4 (Mohs scale); Color: Dark grey to bluish-black with white veining; Luster: Dull/Matte in raw state; Crystal Structure: Trigonal (in veins); Cleavage: Perfect rhombohedral in veins; Specific Gravity: 2.71

Hardness: 3-4 (Mohs scale)
Color: Dark grey to bluish-black with white veining
Luster: Dull/Matte in raw state

Identified April 1, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation of organic remains and chemical precipitation in marine environments. The white veins are secondary calcium carbonate deposits that filled cracks in the rock over millions of years.

Uses & applications

Extensively used in aquascaping (landscape design for aquariums), decorative rock gardens, and construction aggregate.

Geological facts

This specific aesthetic, characterized by sharp edges and white veins, is often referred to as 'Seiryu' in the aquarium trade. It can slowly raise the pH and hardness of water through the release of calcium carbonate.

Field identification & locations

Identify by its dark angular faces and distinctive white 'strike' veins. Field identifies by testing with weak acid (like vinegar), which will cause a slight fizzing reaction on the surface.