Mineral, Specifically A Rock Fragment

Sandstone (Quartzose)

Arenite (SiO2 based)

Lapis Lazuli

Complex mixture of minerals (lazurite, calcite, pyrite, and sodalite); (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2

Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Emerald In Matrix

Beryl (Be3Al2Si6O18) with trace Chromium/Vanadium

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Conglomerate

Conglomerate (clastic sedimentary rock)

Chert (Septarian Concretion/Nodule)

Microcrystalline silica (SiO2) with carbonate mineral veining

Serpentinite (Serpentine Rock)

Primarily composed of serpentine group minerals, such as antigorite, chrysotile, and lizardite. Chemical formula for serpentine minerals is (Mg,Fe)3Si2O5(OH)4.

Gneiss

Gneiss (High-grade Metamorphic Rock)

Granite

Phaneritic Felsic Igneous Rock

Greenstone (Epidote/Chlorite-rich Metabasalt)

Greenschist / Epidosite (Ca2(Al,Fe)3(SiO4)3(OH))

Milky Quartz

Quartz / Silicon Dioxide (SiO2)

Smoky Quartz

Silicon Dioxide (SiO2)

Labradorite

(Ca, Na)(Al, Si)4O8

Yellow Quartz (Citrine or Yellow Jasper)

Silicon Dioxide (SiO2)

Granatic Pegmatite

Pegmatitic Granite

Quartz Pebble

Silicon Dioxide (SiO2)

Diorite

Diorite (Intermediate Plutonic Rock)

Quartzite

Quartzite (Primary mineral: Silicon Dioxide, SiO₂)

Olivine (Peridotite)

(Mg,Fe)2SiO4 (Magnesium Iron Silicate)

Yellow Quartzite (River Pebble)

Quartzite (primarily Silicon Dioxide, SiO2)

Boulder Opal

Precious Opal in Ironstone (Amorphous Hydrated Silica, SiO2·nH2O)

Amethyst Quartz

Silicon Dioxide (SiO2) with iron impurities

Quartz Druzy on Basalt

Silicon Dioxide (SiO2) on Mafic Volcanic Rock

Epidote in Basalt

Epidotized Basalt (Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH) in Mafic Igneous Host)

Concretion (Sandstone)

Sandstone Concretion

Garnet Schist

Garnetiferous Micaceous Schist

Basalt

Extrusive mafic igneous rock

Agate

Silicon Dioxide (SiO2)

Jasper

Silicon dioxide (SiO2) with impurities

Granite Cobble / Rounded Granite River Rock

Granite

Quartz (Milky/Crystal Variety)

Silicon Dioxide (SiO2)

Basalt with Quartz Vein and Weathering Crust

Amygdaloidal or Porphyritic Basalt

Granite

Granite (a felsic intrusive igneous rock)

Vesicular Basalt (Amygdaloidal)

Amygdaloidal Basalt (Mafic volcanic rock)

Sandstone (Ferruginous)

Arenite (composed primarily of SiO2 with Fe2O3 cement)

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Gneiss

Gneiss (High-grade Metamorphic Rock)

Charoite

Charoite (Hydrated potassium sodium calcium barium strontium silicate hydroxyfluoride)

Brecciated Chert

Sedimentary Chert (SiO2) with Calc-Silicate mineralization

Carnelian

Carnelian (SiO2 with Iron Oxide impurities)

Carnelian

Carnelian (a variety of Chalcedony, SiO ₂)