Green Opal
Hydrated Silica (SiO2·nH2O)
mineraloid
Category
Sedimentary (Formed From Silica Deposits)
Browse sedimentary (formed from silica deposits) specimens identified by the Rock Identifier community.
Amethyst (Polished/Carved Crystal)
Silicon Dioxide (SiO2) with trace Iron (Fe)
mineral
Jasper
Silicon dioxide (SiO2)
sedimentary
Sodalite (blue beads) and Clear Quartz (clear beads)
Sodalite: Na4Al3Si3O12Cl; Quartz: SiO2
mineral
Black Onyx
Silicon Dioxide (SiO2)
mineral
Sandstone
Arenite
sedimentary
Milky Quartz
Quartz (Silicon Dioxide - SiO2)
mineral
Chert (Jasper/Flint variant)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (often called Flint when dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Sandstone
Quartz Arenite (a common type of sandstone, given the appearance), Arkose, Greywacke (depending on mineralogy)
Sedimentary Rock
Red Jasper (Brecciated Jasper)
SiO2 (Silicon Dioxide) with Ferric Iron inclusions
sedimentary
Jasper (Yellow Jasper)
Silicon Dioxide (SiO2) with iron inclusions
sedimentary
Turquoise
CuAl6(PO4)4(OH)8·4H2O (Hydrated copper and aluminium phosphate)
mineral
Agate (or Chalcedony)
SiO2 (Silicon Dioxide) - a cryptocrystalline variety of quartz
Mineral
Amethyst (Quartz Cluster)
Silicon Dioxide (SiO2) with iron impurities
mineral
Baltic Amber
Succinite (Polmerized conifer resin)
mineraloid
Banded Calcite (often sold as Caribbean Calcite or Mexican Onyx)
Calcium Carbonate (CaCO3)
mineral
Gold Mineral
Native Gold (Au)
mineral
Howlite
Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)
mineral
Satin Spar (Selenite)
Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O
mineral
Bituminous Coal
Organic-rich sedimentary rock (Complex hydrocarbons)
sedimentary
Bull Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
mineral
Pyrite
Iron Disulfide (FeS2)
mineral
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Red Jasper (possibly Orbicular)
Silicon Dioxide (SiO2) with iron oxide inclusions
sedimentary
Blue Chalcedony
Chalcedony (SiO2)
mineral
Coquina
Biogenic Limestone (Calcium Carbonate - CaCO3)
sedimentary
Pyrite
Iron Sulfide (FeS2)
mineral
Milky Quartz
Quartz (Silicon Dioxide - SiO2)
mineral
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Limonite (also known as Yellow Ochre or Brown Hematite)
Limonite (Hydrated iron oxide-hydroxide, FeO(OH)·nH2O)
Mineral
Chert / Flint
Chert (Microcrystalline Quartz, SiO2)
sedimentary
Orange Calcite
Calcite (Calcium Carbonate, CaCO3)
mineral
Emerald
Beryl (Be3Al2(SiO3)6) with Chromium/Vanadium impurities
mineral
Septarian Nodule (Dragon Stone)
Septarian concretion (Complex of Calcite, Aragonite, and Limestone/Clay)
sedimentary
Native Copper
Native Copper (Cu)
mineral
Clear Quartz Crystal (Herkimer Diamond style)
Silicon Dioxide (SiO2)
mineral
Red Sandstone
Arenite (primarily Quartz SiO2 with Hematite Fe2O3 cement)
sedimentary
Fossil Shell (Bivalve)
Class Bivalvia (Likely a member of the Ostreidae or Gryphaeidae family), CaCO3
sedimentary
Chert (Jasper/Agate variety)
Microcrystalline Quartz (SiO2)
sedimentary
Granite (Pink/Potassium-rich)
Phaneritic Plutonic Felsic Igneous Rock (primarily SiO2 with KAlSi3O8)
igneous
Dendritic Agate
Silicon Dioxide (SiO2) with inclusions
mineral