Amethyst (Quartz)
Silicon Dioxide with Iron impurities (SiO2)
mineral
Category
Basalt
Browse basalt specimens identified by the Rock Identifier community.
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Chalcedony
Silicon dioxide (SiO2) - Microcrystalline quartz
mineral
Eroded Brick or Pumice-like Scoria
Vesicular Basalt / Scoria (Anthropogenic variant: Eroded Firebrick)
igneous
Amethyst
SiO2 (Silicon Dioxide with iron impurities)
mineral
Scoria (Lava Rock)
Scoria (Mafic volcanic rock)
igneous
Amethyst (Faceted)
Silicon Dioxide with Iron impurities (SiO2)
mineral
Pink Amethyst Geode
Silicon Dioxide (SiO2) with Hematite/Iron impurities
mineral
Amygdaloidal Basalt with Quartz/Zeolite Infill
Amygdaloidal Basalt (extrusive volcanic rock with SiO2 or CaAl2Si3O10·3H2O infill)
igneous
Thunderegg (Agetized Geode nodule)
Rhyolitic Agate Nodule (SiO2 filling volcanic cavities)
igneous
Chert on Volcanic Host Rock
Sedimentary Chert (SiO2) within Basalt or Andesite
sedimentary
Vesicular Basalt with Opal or Quartz
Vesicular Basalt (Amorphous SiO2.nH2O if Opal)
igneous
Porphyritic Basalt (Chinese Flower Stone / Chrysanthemum Stone basalt variety)
Porphyritic Basalt containing Plagioclase Feldspar phenocrysts
igneous
River Stone (likely Siltstone or fine-grained Basalt)
Clastic Sedimentary (Siltstone) or Mafic Igneous (Basalt)
sedimentary or igneous
Porphyritic Basalt (Peanut Obsidian/Star Galaxy-style)
Porphyritic Basalt (Silica-rich Volcanic Rock)
igneous
Scoria
Vesicular Basalt / Scoria (Mafic volcanic rock)
igneous
Greenstone Celt (Polished Stone Axe)
Metamorphosed mafic rock (often Basalt or Diabase)
metamorphic
Magnetite
Magnetite (Fe3O4)
mineral
Greenschist (Greenstone River Pebble)
Greenschist (Chlorite Schist)
metamorphic
Greenschist
Chlorite Schist
metamorphic
Amethyst
Amethyst (Silicon Dioxide with iron impurities), SiO2
mineral
Banded Agate with Druzy Quartz
Agate (Silicon Dioxide - SiO2)
mineral
Heat-Treated Citrine (Amethyst Cathedral with Agate inclusions)
Silicon Dioxide (SiO2) with iron impurities
mineral
Schist
Mica Schist (Variable chemistry, often rich in muscovite and biotite)
metamorphic
Lake Superior Agate
Cryptocrystalline Quartz (SiO2)
mineral
Red Scoria (Lava Rock)
Scoria (highly vesicular basaltic/andesitic rock)
igneous
Banded Agate (Lake Superior Agate style)
Silicon Dioxide (SiO2)
mineral
Rough Gemstone Grains (Mixed Sapphires and Quartz)
Corundum (Al2O3) and Quartz (SiO2)
mineral
Native Copper (Penny specimen)
Native Copper (Cu)
mineral
Tanzanite (Rough)
Blue Zoisite (Ca2Al3(SiO4)3(OH))
mineral
Banded Agate
Chalcedony (Silicon Dioxide, SiO2)
mineral
Epidote
Epidote (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))
mineral
Eclogite
Eclogite (Omphacite-Garnet Metamophic Rock)
metamorphic
Blue Sapphire
Corundum (Al2O3)
mineral
Lake Superior Agate
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
sedimentary
Sunstone with Black Tourmaline (Arfvedsonite)
Feldspar (Na,Ca)(Al,Si)4O8 with Schorl Na(Fe3+)3Al6(Si6O18)(BO3)3(OH)3(OH)
mineral
Ruby and Diamond Heart Pendant
Corundum (Al2O3) and Diamond (C)
mineral
Star Sapphire
Corundum (Al2O3) with Rutile inclusions
mineral
Diamond Drill Core (Greenschist and Quartzite)
Chlorite Schist / Meta-quartzite (Metamorphic Rock Core Sample)
metamorphic
Diabase (Greenstone)
Diabase (Dolerite)
igneous
Yellow Chalcedony (Agate/Carnelian variant)
Silicon Dioxide (SiO₂)
mineral
Amethyst (as part of a multi-stone bracelet)
Silicon Dioxide (SiO2) with iron impurities
mineral
Moss Agate
Silicon Dioxide (SiO2) with mineral inclusions of hornblende or chlorite
Mineral (variety of Chalcedony)