Fossiliferous Limestone (often called Fossil Marble)
Sedimentary Limestone containing Fossiliferous inclusions (Calcite) · Decorative Stone / Mineral Specimen
Crystal System
Trigonal (individual calcite crystals); the rock itself is massive/aggregate
Mineral Group
Carbonates
Chemical Formula
CaCO3 (Calcium Carbonate) with possible impurities of SiO2 and Fe2O3
Formation Process
Sedimentary: Formed from the accumulation and lithification of marine skeletal fragments and calcium carbonate mud at the bottom of ancient seas
About This Crystal
An opaque, tan to brownish-grey massive stone with a vitreous to waxy luster when polished. It features prominent fossil inclusions, including visible shell fragments, crinoids, or ammonoid sutures appearing as darker or lighter swirls and patterns
Physical Characteristics
Color: Tan/Beige; Streak: White; Cleavage: None (in massive form); Fracture: Uneven; Specific Gravity: 2.7; Fluorescence: Often dull orange or white under UV
Optical Properties
Opaque in massive form; single calcite crystals within are doubly refractive (though not visible in this specimen); Low dispersion
Hardness & Durability
Origin Region
Found globally; notable sources include Morocco (Erfoud), Italy, and the Midwestern United States
Hardness & Durability
Mohs Hardness: 3; Toughness: Poor to Fair; Very sensitive to acids and easy to scratch; not suitable for heavy-wear jewelry
Care & Maintenance
Clean with a soft, damp cloth only; avoid all acidic cleaners (vinegar, lemon), ultrasonics, and steam. Store away from harder stones like quartz to prevent scratching
Rarity & Value
Common; Value is determined by the aesthetic arrangement of fossils and quality of the carving; generally low-cost decorative material
Special Characteristics
Biogenic inclusions: Contains preserved remains of prehistoric marine organisms that create unique, non-repeating natural patterns
Lore & History
Historically used as a building material and in ornamental sculpture for millennia. Metaphysically associated with the Root Chakra and believed to aid in connecting with the past and promoting longevity