Green Apophyllite on Stilbite
Fluorapophyllite-(K) [(KCa4Si8O20F)·8H2O] and Stilbite [NaCa4(Si27Al9)O72·28H2O]
Category
Browse organic gemstone (often associated with sedimentary sequences) specimens identified by the Rock Identifier community.
Green Apophyllite on Stilbite
Fluorapophyllite-(K) [(KCa4Si8O20F)·8H2O] and Stilbite [NaCa4(Si27Al9)O72·28H2O]
Red Jasper
Jasper (a cryptocrystalline variety of Quartz, SiO₂)
Quartz (Rock Crystal) with minor impurities
Quartz (SiO2)
Chrysocolla in Quartz (Gem Silica)
Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O (Chrysocolla) / SiO2 (Quartz)
Greenstone (Epidote/Chlorite Rich Rock)
Metabasalt (often contains Epidote Ca2Al2(Fe3+;Al)(SiO4)(Si2O7)O(OH))
Turquoise
Turquoise (Hydrated phosphate of copper and aluminium) - CuAl6(PO4)4(OH)8·4H2O
Petrified Wood
Silicified Wood (primarily SiO2 - Silicon Dioxide / Chalcedony)
Pearl
Aragonite / Calcium Carbonate (CaCO3)
Pearl
Aragonite and Conchiolin (CaCO3 + organic protein)
Red Sandstone
Arenite (with Iron Oxide pigmentation)
Basalt
Mafic Volcanic Rock (composed mainly of Plagioclase, Pyroxene, and Olivine)
Porphyry (specifically Porphyritic Rhyolite or Andesite)
Porphyritic Igneous Rock (composed of Phenocrysts in an Aphanitic groundmass)
Red Sandstone
Arenite (with Iron Oxide / Hematite cementation)
Amber with Organic Inclusions
Succinite (fossilized resin)
Fluorite and Red Jasper
Fluorite (Calcium Fluoride, CaF2) and Red Jasper (Silicon Dioxide, SiO2)
Blue Lace Agate
Silicon Dioxide (SiO₂)
Amethyst
Silicon dioxide with iron impurities (SiO2)
Chert (specifically Flint or Gray Chert)
Silicon Dioxide (SiO2)
Fossiliferous Limestone (Gritstone/Marl)
CaCO3 (Calcium Carbonate) with Fossil Inclusions
Fancy Jasper (Agate/Chert mix)
Silicon Dioxide (SiO2) with impurities
Chert (and Quartz Gravel)
Chert (Cryptocrystalline Quartz, SiO2)
Chert (specifically Tan/Yellow Chert)
Silicon Dioxide (SiO2)
Crinoid Stem Fragment
Crinoid (Phylum Echinodermata, Class Crinoidea)
Chert (and/or Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Orthoceras Fossil Limestone
Orthoceras sp. (Calcium Carbonate, CaCO3)
Chert (Jasper/Flint Pebble)
Microcrystalline or Cryptocrystalline Silicon Dioxide (SiO2)
Red Chert (Jasper)
Chert / Microcrystalline Quartz (SiO2)
Black Marble
Recrystallized Limestone (CaCO3)
Amber
Succinite (specifically for Baltic amber); approximate formula C10H16O
Granite
Felsic Intrusive Igneous Rock (SiO2, Al2O3, K2O, Na2O)
Citrine
Silicon Dioxide (SiO2) with iron impurities
Red Amber (Burmite/Cherry Amber)
Succinite / Retinite (Organic Fossilized Resin, C10H16O)
Mookaite Jasper
Silicified Radiolarite (SiO2 with iron impurities)
Banded Calcite (often sold as 'Mexican Onyx' or 'Green Onyx')
Calcite (Calcium Carbonate, CaCO3)
Scoria (Lava Rock)
Vesicular Basalt / Scoria
Chert (and associated Flint)
Silicon Dioxide (SiO2)
Chert (Jasper/Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Banded Chert (Flint)
Microcrystalline Quartz (SiO2)
Chert (specifically a nodule with Chalcendony/Agate banding)
Microcrystalline Quartz (SiO2)
Chert / Flint
Silicon Dioxide (SiO2)
Chert Pebble (Jasper/Quartz variety)
Microcrystalline Quartz (SiO2)
Chert (specifically Red Chert / Flint)
Silicon Dioxide (SiO2)