sedimentary
Limestone with Calcite
Sedimentary Calcium Carbonate (CaCO3)
Hardness: 3 (Mohs scale), Color: Dark grey to light beige/white, Luster: Dull to earthy (matrix) vs vitreous (crystalline parts), Crystal Structure: Trigonal (calcite inclusions), Cleavage: Perfect rhombohedral in calcite areas.
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Physical properties
Hardness: 3 (Mohs scale), Color: Dark grey to light beige/white, Luster: Dull to earthy (matrix) vs vitreous (crystalline parts), Crystal Structure: Trigonal (calcite inclusions), Cleavage: Perfect rhombohedral in calcite areas.
Formation & geological history
Formed in marine environments through the accumulation of shell, coral, and algal debris over millions of years. This specimen shows secondary mineralization where calcite has filled veins or replaced original material.
Uses & applications
Primary use in construction as aggregate, cement production, and as a chemical feedstock for lime. Small decorative specimens are popular for amateur geology collections.
Geological facts
Limestone makes up about 10% of the total volume of all sedimentary rocks on Earth. It is the primary rock type found in karst landscapes, which are known for caves and sinkholes.
Field identification & locations
Identify in the field by applying a drop of dilute hydrochloric acid; it will effervesce (fizz) vigorously. It is commonly found in ancient seabed regions and mountain ranges like the Alps or the Appalachians.
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