Rock Identifier
Fossiliferous Jasper / Miriam Stone / Elephant Skin Jasper (Biogenic Chalcedony / Silicified Fossiliferous Limestone) — fossil
fossil

Fossiliferous Jasper / Miriam Stone / Elephant Skin Jasper

Biogenic Chalcedony / Silicified Fossiliferous Limestone

Hardness: 6.5-7 on Mohs scale. Color: Warm brown, golden yellow, ochre, and deep orange-red. Luster: Vitreous to waxy when polished. Structure: Microcrystalline quartz replacing organic marine fossils. Cleavage: None (conchoidal fracture). Specific Gravity: ~2.6-2.7.

Hardness
6
Color
Warm brown, golden yellow, ochre, and deep orange-red
Luster
Vitreous to waxy when polished
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Physical properties

Hardness: 6.5-7 on Mohs scale. Color: Warm brown, golden yellow, ochre, and deep orange-red. Luster: Vitreous to waxy when polished. Structure: Microcrystalline quartz replacing organic marine fossils. Cleavage: None (conchoidal fracture). Specific Gravity: ~2.6-2.7.

Formation & geological history

Formed in ancient marine or lacustrine environments where shell fragments, bone fragments, or algae were gradually replaced by silica (chalcedony) over millions of years under high pressure and heat. Commonly associated with Cretaceous to Tertiary marine deposits.

Uses & applications

Popular in lapidary arts for creating polished cabochons, tumbled stones, beads, carved ornaments, and metaphysical crystal collecting.

Geological facts

Often marketed under trade names like 'Miriam Stone', 'Elephant Skin Jasper', or 'Calligraphy Stone', this material contains silicified ancient shell and coral debris that create intricate, script-like yellow patterns on a dark reddish-brown background.

Field identification & locations

Can be identified by the distinct yellow-gold, shell-like or swirl patterns suspended inside a translucent to opaque dark brown matrix. Commonly sourced from the Himalayan regions of India and parts of North Africa and the American Southwest.

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