Crystals
Sugilite
Sugilite · lithium-bearing double-ring silicate of the milarite–osumilite structural family KNa₂(Fe³⁺,Mn³⁺,Al)₂Li₃Si₁₂O₃₀ Hexagonal · rare crystals, commonly granular to massive Purple color · principally associated with Mn³⁺ in gem material Mohs...
Sugilite
Sugilite · lithium-bearing double-ring silicate of the milarite–osumilite structural family KNa₂(Fe³⁺,Mn³⁺,Al)₂Li₃Si₁₂O₃₀ Hexagonal · rare crystals, commonly granular to massive Purple color · principally associated with Mn³⁺ in gem material Mohs...
Scolecite
Scolecite · calcium-bearing zeolite of the natrolite subgroup CaAl₂Si₃O₁₀·3H₂O Monoclinic · commonly pseudotetragonal in outward form Mohs 5–5.5 · brittle despite its moderate hardness Radiating sprays · slender prisms ·...
Scolecite
Scolecite · calcium-bearing zeolite of the natrolite subgroup CaAl₂Si₃O₁₀·3H₂O Monoclinic · commonly pseudotetragonal in outward form Mohs 5–5.5 · brittle despite its moderate hardness Radiating sprays · slender prisms ·...
Sea urchin
Sea Urchin Fossils • Class Echinoidea • calcitic echinoderm tests, spines, jaws, molds, and casts Fossil record • Late Ordovician to Recent Core plan • five ambulacra alternating with five...
Sea urchin
Sea Urchin Fossils • Class Echinoidea • calcitic echinoderm tests, spines, jaws, molds, and casts Fossil record • Late Ordovician to Recent Core plan • five ambulacra alternating with five...
Rutile quartz
Rutilated Quartz • quartz, SiO₂, enclosing acicular crystals of rutile, TiO₂ Needle colors • pale gold, yellow-orange, copper, red-brown, silver-gray, and dark brown Structures • isolated needles, parallel bundles, sagenitic...
Rutile quartz
Rutilated Quartz • quartz, SiO₂, enclosing acicular crystals of rutile, TiO₂ Needle colors • pale gold, yellow-orange, copper, red-brown, silver-gray, and dark brown Structures • isolated needles, parallel bundles, sagenitic...
Shark teeth
Fossil Shark Teeth • mineralized dental remains of sharks and related cartilaginous fishes Crown • highly mineralized enameloid over dentine Root • porous dentine-rich anchoring tissues Fossil color • controlled...
Shark teeth
Fossil Shark Teeth • mineralized dental remains of sharks and related cartilaginous fishes Crown • highly mineralized enameloid over dentine Root • porous dentine-rich anchoring tissues Fossil color • controlled...
Red tiger eye
Red Tiger Eye • chatoyant quartz-rich aggregate with aligned, altered riebeckite-crocidolite fiber trails Trade names • bull’s-eye and ox’s-eye Color • hematite-rich red, rust, brick, and mahogany Optical effect •...
Red tiger eye
Red Tiger Eye • chatoyant quartz-rich aggregate with aligned, altered riebeckite-crocidolite fiber trails Trade names • bull’s-eye and ox’s-eye Color • hematite-rich red, rust, brick, and mahogany Optical effect •...