Chert (often called Flint or River Rock)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Category
Browse sedimentary (secondary mineral formation) specimens identified by the Rock Identifier community.
Chert (often called Flint or River Rock)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
Chert (specifically Flint or Common Chert)
Microcrystalline Quartz (SiO2)
Fossiliferous Limestone
Limestone (composed primarily of calcite with included fossils CaCO3)
Ocean Jasper (Orbicular Jasper)
Silicon Dioxide (SiO2)
Chalk
CaCO3 (primarily Calcium Carbonate), biogenic sedimentary rock
Chert / Flint (a variety of Chert)
Chert (SiO2)
Banded Gneiss
Gneiss (pronounced 'nice')
Jasper (specifically Red or Brecciated Jasper variant)
Jasper (Microcrystalline Quartz - SiO2)
Lapis Lazuli (Raw)
Lazurite-rich metamorphic rock; Na3Ca(Al3Si3O12)S
Amethyst
SiO2 (Silicon Dioxide with Iron impurities)
Chert (Nodule)
Silicon Dioxide (SiO2)
Banded Onyx (Calcite Marble)
Calcite (CaCO3) - Trap-rock or Cave Onyx
Red Jasper
Jasper (SiO2 with Fe2O3 inclusions)
Peridot and Citrine Gemstones (in a ring setting)
Peridot (Olivine: (Mg,Fe)2SiO4), Citrine (Quartz: SiO2)
Quartzite with Iron Hydroxide Staining
Quartzite (primarily SiO2) with Limonite/Goethite staining
Basalt with Calcite Veins
Basalt (containing CaCO3 inclusions)
Green Aventurine
Silicon Dioxide (SiO2) with Fuchsite inclusions
Moonstone (bead form)
Potassium Aluminum Silicate (KAlSi3O8) - a variety of Orthoclase Feldspar
Included Quartz (Garden Quartz / Lodolite)
Quartz (SiO2) with various mineral inclusions
Banded Iron Formation
Banded Iron Formation (BIF)
Quartz (Druzy) in host rock
SiO₂ (Silicon Dioxide) as Quartz, with unspecified host rock components (likely silicates and iron oxides)
Opalite
Opalescent Glass (SiO2 + coloring agents)
Blue Agate (Dyed Chalcedony)
Silicon Dioxide (SiO2)
Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Lapis Lazuli
Lapis Lazuli (a rock composed primarily of Lazurite)
Black Pearl (Tahitian Type)
Aragonite / Conchiolin composite (CaCO3)
Yellow Jadeite
NaAlSi2O6 (Sodium Aluminum Silicate)
Green glass sphere/marble
Soda-lime glass (primarily SiO2, Na2O, CaO)
Zebra Jasper
Silicon dioxide (SiO2) with various impurities
Gold Nugget
Native Gold (Au)
Moss Agate
Silicon Dioxide (SiO2) with inclusions
Black Tourmaline
Schorl (Na(Fe²⁺)₃Al₆(OH)₄(BO₃)₃Si₆O₁₈)
Black Chert
Chert (microcrystalline quartz)
Banded Gneiss
Gneiss (pronounced "nice")
Bumble Bee Jasper
Volcanic Tuff (mixture of SiO2, CaCo3, S, and As2S3)
Tiger's Eye
Tiger's Eye (SiO2 with crocidolite inclusions)
Alexandrite
Chrysoberyl (BeAl2O4 with Chromium impurities)
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
Jasper (Red Jasper)
Silicon Dioxide (SiO₂)
Carnelian (Chalcedony variety)
SiO2 (Silicon Dioxide)
Sandstone (likely a river or beach pebble)
Sandstone (a clastic sedimentary rock)