Amethyst
Amethyst (Silicon Dioxide - SiO2 with iron impurities)
mineral
Category
Not A Natural Rock
Browse not a natural rock specimens identified by the Rock Identifier community.
Sandstone
Arenite (SiO2 predominantly)
sedimentary
Amber
Succinite (specifically for Baltic amber); Approximate formula: C10H16O
Organic Gemstone (Mineraloid)
Amber
Succinite (Formula: C10H16O)
mineral
Obsidian
Obsidian (Amorphous volcanic glass, SiO2 with impurities)
igneous
Aragonite (Onyx Marble)
Calcium Carbonate (CaCO3), Orthorhombic crystal system
mineral
Limonite and Goethite encrusted Chert/Ironstone
Hydrated Iron Oxide (FeO(OH)·nH2O) with cryptocrystalline Silica (SiO2)
sedimentary
Amethyst
Silicon Dioxide (SiO2) with iron impurities
mineral
Yellow Quartz (Citrine/Yellow Chalcedony)
Silicon Dioxide (SiO2)
mineral
Mexican Crazy Lace Agate
Silicon Dioxide (SiO2) with iron and aluminum inclusions
mineral
Amber
Succinite (fossilized resin)
mineral
Limonite with Quartz (Gossan)
Hydrated iron(III) oxide-hydroxide mixture (FeO(OH)·nH2O) with Silicon Dioxide (SiO2)
Mineral
Amber
Succinite
mineraloid
Amber
Succinite (a Fossilized Tree Resin); Chemical formula is approximately C10H16O
Organic mineraloid
Limonite (with Pyrite)
Limonite (Hydrated Iron Oxide) - FeO(OH)·nH2O
mineral
Green Fluorite
Fluorite (Calcium Fluoride, CaF2)
mineral
Fluorite
Calcium Fluoride (CaF2)
mineral
Sandstone
Arenite (SiO2 based with various mineral cements)
sedimentary
Quartz in Host Rock
Silicon Dioxide (SiO2) in Rhyolite or Granite matrix
igneous
Amphibolite
Amphibolite
metamorphic
Quartz Vein in Host Rock (Pebble)
Quartz (SiO2) with sandstone or siltstone matrix
metamorphic/igneous transition
Jasper (Chert)
Silicon Dioxide (SiO2)
sedimentary
Acrylic or Resin (Synthetic Imitation)
Polymethyl Methacrylate (PMMA) or Polyepoxide
Synthetic/Man-made Polymer
Thunderegg (Ate Agate/Jasper Geode)
Silicon Dioxide (SiO2) within Rhyolite/Perlite matrix
sedimentary/igneous intermediary
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Vesicular Basalt (River Rock)
Afanitic Vesicular Basalt
igneous
Sandstone (Ferruginous)
Clastic Sedimentary Rock (SiO2 with FeO/Fe2O3)
sedimentary
Gold in Quartz Matrix
Native Gold (Au) with Quartz (SiO2) and Slate/Shale
mineral
Biotite Schist
Biotite Schist (Rich in K(Mg,Fe)3AlSi3O10(OH)2)
metamorphic
Gneiss
High-grade Metamorphic Gneiss
metamorphic
Banded Sandstone (Liesegang Rings)
Sedimentary Arenite (SiO2 with FeO/Fe2O3 impurities)
sedimentary
K2 Jasper (Beads)
Granodiorite with Azurite and Malachite
igneous
Emerald
Beryl (variety Emerald), Be3Al2Si6O18 with Cr and/or V
Mineral
Painted River Rock
Anthropogenic-modified Siliciclastic Sedimentary Rock
Sedimentary
Ferruginous Sandstone
Arenite with Iron-oxide cement
sedimentary
Basalt
Mafic extrusive volcanic rock (composed primarily of Plagioclase feldspar and Pyroxene)
igneous
Grey Agate (Tumbled)
Silicon Dioxide (SiO2)
mineral
Amber (Rough)
Amber (Fossilized Tree Resin, succinite)
mineral
Limonite (Iron Ore)
FeO(OH)·nH2O (Hydrous ferric oxide)
mineral
Amber
Resinite (Succinite if from the Baltic); Chemical Formula: C10H16O (approximate)
Organic Diamond/Gemstone (often associated with Sedimentary sequences)
Amber
Succinicum (Organic Gemstone - Resinite)
mineraloid
Snowflake Obsidian
Volcanic glass with Cristobalite inclusions (mostly SiO2)
igneous