Fossilized Bryozoan
Calcite var. Fossilized Bryozoa (Phylum Bryozoa) · Mineral Specimen / Fossil Gemstone
Crystal System
Trigonal (as microcrystalline calcite replacements) / Habit is Colonial, lace-like, or moss-like fenestrated patterns
Mineral Group
Carbonates (Calcite mineral group)
Chemical Formula
CaCO3 (Calcium Carbonate with possible trace Fe, Mg, or SiO2 replacements)
Formation Process
Sedimentary: Biogenic precipitation where marine microorganisms built calcium carbonate skeletons, eventually becoming lithified in limestone.
About This Crystal
The specimen features a distinctive 'honeycomb' or 'net-like' (fenestrate) lattice structure typical of bryozoans. Color ranges from tan to greyish-white, with a dull to earthy luster and opaque transparency.
Physical Characteristics
Color: Tan/Beige; Streak: White; Cleavage: None (in fossil form); Fracture: Uneven/Splintery; Specific Gravity: ~2.7; Fluorescence: Often dull orange or yellow under UV.
Optical Properties
Sub-glassy to earthy luster; no significant birefringence or pleochroism in raw fossilized state; non-refractive in massive matrix.
Hardness & Durability
Origin Region
Globally distributed; notable deposits in North America, Europe, and Russia. Found in marine sedimentary limestone layers.
Hardness & Durability
Mohs Hardness: 3.0 - 4.0; Toughness is poor as it is brittle; low durability for jewelry compared to silicates.
Care & Maintenance
Avoid acidic cleaners (which dissolve calcium carbonate); clean with soft brush and distilled water; keep away from harder gemstones; avoid ultrasonic cleaners.
Rarity & Value
Common as geological specimens; value is generally low ($5-$30 for hand samples), depending on the preservation of the delicate lattice structures.
Special Characteristics
Fenestrate pattern (lace-like structure), porous prehistoric cellular architecture, and carbonaceous inclusions.
Lore & History
Historically used as indicators for ancient marine environments. Metaphysically associated with structural stability, link to the past, and collective consciousness due to the colonial nature of the organisms.