Basalt rock specimen

Basalt

Mafic volcanic rock (Silicon dioxide 45-52%)

igneous

Ironstone Concretion (Nutstone) rock specimen

Ironstone Concretion (Nutstone)

Ironstone (with High Limonite/Hematite Content)

sedimentary

Concretion (Sandstone) rock specimen

Concretion (Sandstone)

Carbonate-cemented Sandstone Concretion

sedimentary

Green Calcite rock specimen

Green Calcite

Calcium Carbonate (CaCO3)

mineral

Rose Quartz rock specimen

Rose Quartz

Silicon dioxide (SiO2)

mineral

Carnelian (Carnelian Agate) rock specimen

Carnelian (Carnelian Agate)

Silicon dioxide (SiO2) - a variety of Chalcedony

mineral

Tiger's Eye rock specimen

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxide inclusions)

Mineral

Quartzite rock specimen

Quartzite

Quartzite (primarily SiO2)

metamorphic

Sandstone (Quartzose Sandstone) rock specimen

Sandstone (Quartzose Sandstone)

Arenite (primarily SiO2)

sedimentary

Milky Quartz Pebble rock specimen

Milky Quartz Pebble

Silicon Dioxide (SiO2)

mineral

Yellow Quartz Pebble rock specimen

Yellow Quartz Pebble

Silicon Dioxide (SiO2)

mineral

Amethyst (Tumbled) rock specimen

Amethyst (Tumbled)

Purple Quartz (SiO2 with iron impurities and irradiation)

mineral

Chert (often called Flint or River Rock) rock specimen

Chert (often called Flint or River Rock)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

sedimentary

Red Jasper rock specimen

Red Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

sedimentary

Gneiss rock specimen

Gneiss

Gneissic Metamorphic Rock

metamorphic

Carnelian Agate rock specimen

Carnelian Agate

Carnelian (SiO2 with iron oxide impurities)

mineral

Clear Quartz rock specimen

Clear Quartz

Silicon Dioxide (SiO2)

mineral

Sandstone (Micaceous) rock specimen

Sandstone (Micaceous)

Arenite (composed primarily of SiO2)

sedimentary

Amethyst Geode rock specimen

Amethyst Geode

Silicon Dioxide with trace inclusions of Iron (SiO2)

mineral

Mica Schist rock specimen

Mica Schist

Mica Schist (Schistose metamorphic rock rich in Muscovite/Biotite)

metamorphic

Rhyolite rock specimen

Rhyolite

Rhyolite (Extrusive Igneous Rock)

igneous

Quartzite Pebble rock specimen

Quartzite Pebble

Metamorphic Quartz (SiO2)

metamorphic

Granite rock specimen

Granite

Phaneritic Felsic Intrusive Igneous Rock

igneous

Milky Quartz rock specimen

Milky Quartz

Silicon Dioxide (SiO2)

mineral

Red Jasper (River Stone) rock specimen

Red Jasper (River Stone)

Jasper (Silicon Dioxide, SiO2 plus iron oxide inclusions)

sedimentary

Petrified Wood rock specimen

Petrified Wood

Silicified Wood (SiO2)

sedimentary

Amethyst (Agate/Chalcedony variety) rock specimen

Amethyst (Agate/Chalcedony variety)

Silicon Dioxide (SiO2) with iron impurities

mineral

Amethyst (Agate/Chalcedony variety) rock specimen

Amethyst (Agate/Chalcedony variety)

Silicon Dioxide (SiO2) with iron impurities

mineral

Purple Agate (Dyed Chalcedony) rock specimen

Purple Agate (Dyed Chalcedony)

SiO2 (Silicon Dioxide) with organic dyes

mineral

Charoite rock specimen

Charoite

Charoite (K(Ca,Na)2Si4O10(OH,F)·nH2O)

metamorphic

Purple Chalcedony (likely dyed Agate) rock specimen

Purple Chalcedony (likely dyed Agate)

Silicon Dioxide (SiO2)

mineral

Amber rock specimen

Amber

Succinite (Fossilized Tree Resin)

mineral

Amethyst (Digital/Conceptual Representation) rock specimen

Amethyst (Digital/Conceptual Representation)

Amethyst (Silicon Dioxide with iron impurities, SiO2)

mineral

Amethyst rock specimen

Amethyst

Silicon Dioxide (SiO2) with iron impurities

mineral

Ruby rock specimen

Ruby

Corundum (Al2O3 with Chromium impurities)

mineral

Granite (Alkali-feldspar Granite) rock specimen

Granite (Alkali-feldspar Granite)

Granite (composed primarily of Quartz, K-Feldspar, and Plagioclase)

Igneous

Milky and Ferruginous Quartz rock specimen

Milky and Ferruginous Quartz

Silicon Dioxide (SiO2)

mineral

Quartzite rock specimen

Quartzite

Quartzite (primarily SiO2)

metamorphic

Quartzite with Iron Inclusions rock specimen

Quartzite with Iron Inclusions

Quartzite (primarily SiO2)

metamorphic

Orthoclase Feldspar rock specimen

Orthoclase Feldspar

Orthoclase (KAlSi3O8)

mineral

Basalt rock specimen

Basalt

Mafic volcanic rock (Primary minerals: Plagioclase feldspar, Pyroxene)

igneous

Red Granite rock specimen

Red Granite

Potassium-feldspar rich Granite

igneous