Biotite or Phlogopite Mica
K(Mg,Fe)3(AlSi3O10)(F,OH)2
mineral
Category
Crystal
Browse crystal specimens identified by the Rock Identifier community.
Lepidolite with Quartz
K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2
mineral
Quartz (with iron oxide staining)
Silicon Dioxide (SiO2)
mineral
Garden Quartz (Shaman Quartz)
Silicon Dioxide (SiO2) with various inclusions (Hematite, Chlorite, Feldspar)
mineral
Basalt Porphyry (River Pebble)
Porphyritic Basalt
igneous
Granite (Orthoclase rich)
Granite (composed primarily of Quartz and Potassium Feldspar KAlSi3O8)
igneous
Mica-rich Pegmatite
Pegmatite (rich in Muscovite and Biotite)
igneous
Quartz (White/Milky Pebble)
Silicon Dioxide (SiO2)
mineral
Quartzite (specifically Milky Quartz variety)
Quartz (SiO2)
metamorphic
Quartz (Milky or White Quartz)
Silicon Dioxide (SiO2)
mineral
Epidosite (Unakite-related)
Epidosite (predominantly Epidote, Ca2(Al2,Fe3+)(SiO4)3(OH))
metamorphic
Quartzite River Rock
Quartzite (primarily SiO2)
metamorphic
Stilbite
Stilbite-Ca (Hydrated calcium sodium aluminum silicate), NaCa4(Si27Al9)O72·28H2O
mineral
Goldstone (Brown/Gold variety)
Aventurine Glass (SiO2 with Copper inclusions)
Synthetic/Man-made glass (often mistaken for a mineral)
Rose Quartz
Quartz (Silicon Dioxide - SiO2)
mineral
Rose Quartz
Rose Quartz (SiO2 - Silicon Dioxide with trace amounts of titanium, iron, or manganese)
mineral
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
mineral
Amethyst Quartz (Amethyst Geode)
Silicon Dioxide (SiO2) with iron impurities
mineral
Amethyst
Silicon dioxide (SiO2)
mineral
Marble
Crystalline Limestone (mostly CaCO3 / Calcium Carbonate)
metamorphic
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
mineral
Rose Quartz
Silicon Dioxide (SiO2)
mineral
Chert (Flint nodule)
Silicon dioxide (SiO2)
sedimentary
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Jasper with Quartz inclusion
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Amethyst
Silicon Dioxide with trace inclusions of Iron (SiO2)
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Peridot
Olivine (specifically, the gem-quality variety forsterite, (Mg,Fe)2SiO4)
Mineral
Concretion or Geode (unbroken)
Varied (depending on mineral composition and cementing agent). For quartz-lined geodes, the scientific name of the dominant mineral would be Quartz (SiO2). For calcite-lined geodes, Calcite (CaCO3). Concretions are often composed of cryptocrystalline quartz (chert), calcite, or iron oxides.
Sedimentary rock (specifically a concretion or possibly a geode)
Snowflake Obsidian
Spherulitic Volcanic Glass (SiO2 + impurities)
igneous
Ferruginous Quartz
Silicon Dioxide (SiO2) with Iron Oxide inclusions
mineral
Mahogany Obsidian or Red Jasper
Silicon Dioxide with Iron Oxide (SiO2+Fe2O3)
Mineral/Igneous (Volcanic Glass)
Basalt
Mafic Igneous Rock
igneous
Milky Quartz
Quartz (Silicon Dioxide - SiO2)
mineral
Milky Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
mineral
Milky Quartz with Epidote or Chlorite inclusions
Silicon Dioxide (SiO2) with inclusions of Epidote {Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
White Marble (Tumbled)
Recrystallized Calcite (CaCO3)
metamorphic
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Granite
Granite (composed primarily of Quartz SiO2 and Feldspar (KAlSi3O8 – NaAlSi3O8 – CaAl2Si2O8))
igneous