Magnetite (potentially Hematite-rich)
Magnetite (Fe3O4)
mineral
Category
Sedimentary (Secondary Mineral) Within Igneous
Browse sedimentary (secondary mineral) within igneous specimens identified by the Rock Identifier community.
Amethyst
SiO2 (Silicon Dioxide)
Mineral
Druzy Quartz
Silicon Dioxide (SiO2)
mineral
Labradorite
(Ca, Na)(Al, Si)4O8
mineral
Amethyst
SiO2 (Silicon Dioxide) - a variety of Quartz
Mineral
Dalmatian Stone
Peralkaline rhyolite
igneous
Shale (with Iron Oxide staining)
Fissile Mudstone (primarily Quartz and Clay minerals)
sedimentary
Amethyst
Silicon Dioxide (SiO2) with iron impurities
mineral
Granitic Quartz (with Feldspar inclusions)
Quartz (SiO2) with Potassium Feldspar (KAlSi3O8)
igneous
Snowflake Obsidian
Volcanic glass with Cristobalite inclusions (mostly SiO2)
igneous
Howlite
Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)
mineral
Turquoise
Hydrated phosphate of copper and aluminum, CuAl6(PO4)4(OH)8·4H2O
mineral
Howlite
Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)
mineral
Eudialyte in Syenite (Dragon Blood Stone)
Na15Ca6(Fe,Mn)3Zr3(Si25O73)(O,OH,H2O)3(Cl,OH)2
igneous
Gneiss (Metamorphic Rock)
Gneiss
metamorphic
Sulfur
Native Sulfur (S8)
mineral
Amazonite
Potassium aluminum silicate (KAlSi3O8)
mineral
Chert (with Quartz Vein)
Microcrystalline silica (SiO2)
sedimentary
Olivine (Peridot when gem-quality)
Olivine Group (Magnesium Iron Silicate, (Mg,Fe)2SiO4)
mineral
Sandstone
Arenite (often composed of Quartz, SiO2)
sedimentary
Sandstone (Ferruginous)
Arenite (with high iron oxide content)
sedimentary
Amethyst (Polished/Carved Crystal)
Silicon Dioxide (SiO2) with trace Iron (Fe)
mineral
Granite
Granite
igneous
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Peridot (likely, given the color and bead form)
Olivine, variety Peridot (Mg,Fe)2SiO4
Mineral
Granite Pebble
Felsic Intrusive Igneous Rock (composed of Quartz, Alkali Feldspar, and Plagioclase)
igneous
Basalt with Limonite stains
Extrusive mafic igneous rock; Limonite (FeO(OH)·nH2O)
igneous
Chalcedony (Agate Pebble)
Silicon Dioxide (SiO2)
mineral
Celadonite in Amygdaloidal Basalt
K(Mg,Fe2+)(Fe3+,Al)Si4O10(OH)2 (Celadonite mineral) within a Basalt matrix
igneous
Quartz / Calcite Vein Rock
Silicon Dioxide (SiO2) or Calcium Carbonate (CaCO3)
mineral
Eudialyte in Matrix
Na15Ca6(Fe,Mn)3Zr3(Si,Nb) (Si25O73) (OH,Cl,H2O)3
mineral
Vesicular Basalt with Lichen
Vesicular Basalt
igneous
Limonite-pseudomorph after Pyrite (Prophecy Stone)
Goethite and Limonite secondary minerals (FeO(OH)·nH2O) replacing Pyrite (FeS2)
mineral
Weathered Sandstone with Algae Growth
Arenite
sedimentary
Celestine (Celestite)
Strontium sulfate (SrSO4)
mineral
Quartz (Tumbled)
Silicon Dioxide (SiO2)
mineral
Citrine
Silicon Dioxide (SiO2) with iron impurities
mineral
Epidote in Basalt
Epidotized Basalt (Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH) in Mafic Igneous Host)
igneous
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Agate (Water-Worn Pebble)
Silicon Dioxide (SiO2) - Chalcedony
mineral
Quartz (Iron-stained or Rose variant)
Silicon Dioxide (SiO2)
mineral
Banded Gneiss (with possible weathered sulfide or iron staining)
Gneiss, potentially with iron oxide/hydroxide staining (e.g., limonite) or weathered sulfides
Metamorphic