sedimentary

Limestone with Calcite Veins

Calcium Carbonate (CaCO3)

Hardness: 3 (Mohs scale); Color: Dark grey to bluish-black matrix with white veins; Luster: Dull to earthy (matrix), vitreous (veins); Cleavage: Perfect rhombohedral in calcite portions; Specific Gravity: 2.71.

Hardness: 3 (Mohs scale)
Color: Dark grey to bluish-black matrix with white veins
Luster: Dull to earthy (matrix), vitreous (veins)

Identified June 25, 2026More sedimentary →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed in marine environments from the accumulation of shell, coral, and algal debris. The white veins are secondary calcite deposits that filled fractures within the stone via hydrothermal fluids or groundwater over millions of years.

Uses & applications

Used primarily in construction for building stone, aggregate for concrete, and the production of cement. Distinctive veined specimens are sometimes used for decorative landscaping or small carvings.

Geological facts

Limestone makes up about 10% of the total volume of all sedimentary rocks. The presence of white veins often indicates tectonic activity that cracked the original rock, allowing mineral-rich water to seep in and crystallize.

Field identification & locations

Identified in the field by its reaction (fizzing) to dilute hydrochloric acid. It is commonly found in mountain ranges that were once ancient sea beds, such as the Alps or the Appalachians. To collect, look for eroded pebbles in riverbeds or near limestone cliffs.

Other sedimentary specimens

See all

Sandstone or Siltstone

Arenite (if sandstone)

Sedimentary

Chert Breccia

Brecciated Chert (Microcrystalline Silica)

sedimentary

Sandstone

Arenite (primarily SiO2)

sedimentary

Sandstone Grain

Clastic Sedimentary Rock Grain (SiO2 dominated)

sedimentary

Shale or Slaty Mudstone

Argillaceous sedimentary rock

sedimentary

Sandstone

Arenite

sedimentary