Black Opal
Hydrated Silica (SiO2·nH2O)
mineral
Category
Sedimentary (Biogenic)
Browse sedimentary (biogenic) specimens identified by the Rock Identifier community.
Limonite (Iron Ore)
FeO(OH)·nH2O (Hydrated Iron Oxide)
mineral
Petrified Wood
Silicified Wood (primarily SiO2)
metamorphic
Puddingstone
Conglomerate (specifically a type of jasper conglomerate or quartz conglomerate)
Sedimentary
Leopardskin Jasper
Jasper (a variety of microcrystalline Quartz)
Sedimentary
River Stone / Pebble
Clastic Sediment (composed largely of Quartz, Feldspar, and various rock fragments)
Mineral, Sediment
Magnetite
Magnetite (Fe3O4)
Mineral
Quartz (likely) or a Quartzite Pebble
Silicon dioxide (SiO2) for quartz. If it's quartzite, it's a metamorphic rock primarily composed of quartz.
Mineral, specifically a detrital grain
Celestine (or Celestite) Geode
Strontium Sulfate (SrSO4)
mineral
Quartz (Clear Quartz)
Silicon Dioxide (SiO2)
mineral
Chert (Tan/Grey variety)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Pyrite
Iron Sulfide (FeS2)
mineral
Clear Quartz (Rock Crystal)
Quartz (Silicon Dioxide, SiO2)
mineral
Chert (Field-collected Arrowhead-shaped Fragment)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Green Jasper
Jasper (Silicates, SiO2)
sedimentary
Galena
Lead Sulfide (PbS)
mineral
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Optical Calcite (Iceland Spar)
Calcium Carbonate (CaCO3)
mineral
Jasper with Dendritic Inclusions
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Agate
Silicon Dioxide (SiO2) - variety Chalcedony
mineral
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Pyrite (Fools Gold)
Iron Sulfide (FeS2)
mineral
Amethyst Geode
Silicon Dioxide (SiO2) with iron impurities
mineral
White Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
mineral
Chert (Jasper/Common Opal mix)
Microcrystalline Quartz (SiO2)
sedimentary
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Chalcedony (Botryoidal)
Silicon Dioxide (SiO2)
mineral
Clear Quartz Cluster
Silicon Dioxide (SiO2)
mineral
Mixed Tumbled Gemstones and River Rocks
Mixed Decorative Stones (predominantly Silicon Dioxide - SiO2 variants)
Mixed (Igneous, Sedimentary, Metamorphic, and Minerals)
Picture Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
sedimentary
![Turquoise (Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]) — mineral](https://media.rockidentification.com/81546651-32fa-4148-838a-c2bca7c29bba-thumbnail.jpg)
Turquoise
Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]
mineral
Blue Apatite
Apatite (Calcium Phosphate) - Ca5(PO4)3(F,Cl,OH)
mineral
Pyrite
Iron Disulfide (FeS2)
mineral
Yellow Jasper
Jasper (Silicon Dioxide, SiO2)
sedimentary
Clear Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Iron-stained Quartzite / Chert
Silicon Dioxide (SiO2) with Hematite/Limonite impurities
metamorphic
Agate (specifically a small Chalcedony nodule)
Agate (Cryptocrystalline variety of Quartz, SiO2)
mineral
Red Jasper
Jasper (SiO2) with Hematite (Fe2O3) inclusions
sedimentary (microcrystalline quartz)
Satin Spar (Selenite Gypsum Sphere)
Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O
mineral
Chert (Jasper type)
Microcrystalline Quartz (SiO2)
sedimentary
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
mineral