Mineral Group

Rutilated Prehnite

Prehnite - Ca2Al(AlSi3O10)(OH)2 with Epidote/Tourmaline inclusions

Quartzite Pebble

Quartzite (primarily SiO2)

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Blue Quartz (Aventurine)

Silicon Dioxide (SiO2) with fibrous inclusions (commonly Dumortierite)

Quartz Pebble

Silicon Dioxide (SiO2)

Blue Apatite

Apatite (Ca5(PO4)3(F,Cl,OH))

Chert (Red Jasper variant)

Microcrystalline Quartz (SiO2)

Quartz Pebble

Crystalline Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Geode (unopened)

SiO2 - Chert-shelled concretion (mostly Quartz)

Corundum (Ruby Variety)

Corundum (Al2O3)

Schist

Mica Schist

Granite

Phaneritic Igneous Rock (Granite)

Amygdaloidal Basalt with Epidote

Vesicular Basalt with secondary Epidote/Quartz mineral infill

Quartzite River Rock with Dendrites

Metamorphosed Quartz-rich Sandstone with Manganese Oxide (MnO2) inclusions

Honeycomb Calcite

Calcite (Calcium Carbonate, CaCO3)

Pink Granite (with Potassic Feldspar and Quartz)

Felsic Intrusive Igneous Rock (Granite)

Milky Quartz

Silicon Dioxide (SiO2)

Granite

Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)

Dark-colored Igneous Rock (likely Basalt or Diabase)

Basalt (extrusive igneous) or Diabase (intrusive igneous)

Black Sapphire

Corundum (Al2O3 with iron and titanium impurities)

Milky Quartz

Silicon Dioxide (SiO2)

Kimberlite with Diamond

Kimberlite (Diamond formula: C)

Diorite (Polished River Pebble)

Diorite (Intermediate intrusive igneous rock)

Gneiss

Gneiss (Metamorphic rock composed primarily of quartz, feldspar, and mica)

Mica Schist with Quartz

Mica-Quartz Schist (Muscovite subclass)

Diorite

Diorite (plutonic igneous rock)

Shale

Fissile Mudrock (Clay-rich Sedimentary Rock)

Pink Granite

Phaneritic Felsic Intrusive Igneous Rock

Rhodochrosite

Manganese Carbonate (MnCO3)

Blue Apatite

Fluorapatite (Ca5(PO4)3F)

Sandstone

Sandstone (arenite is a more specific geological term for a clean sandstone, while wacke refers to a dirty sandstone with significant matrix)

Strawberry Quartz

Quartz (SiO2) with inclusions of Goethite or Hematite

Azurite-Malachite (often a mixed specimen)

Azurite: Cu3(CO3)2(OH)2; Malachite: Cu2(CO3)(OH)2. The specimen appears to be a natural mixture or intergrowth of these two minerals.

Vesicular Basalt with Secondary Mineral Inclusions

Aphanitic Mafic Igneous Rock (primarily Plagioclase and Pyroxene)

Limonite (Iron Stone/Ocher)

Limonite (FeO(OH)·nH2O)

Pyrite

Iron Disulfide (FeS2)

Limestone with Quartz/Calcite Veins

Sedimentary Limestone (CaCO3 with SiO2 or CaCO3 intrusions)

Greenstone

Greenschist (containing chlorite, epidote, and actinolite)

Geode with Iron-Stained Quartz/Calcite

Silicon Dioxide (SiO2) or Calcium Carbonate (CaCO3) in Sedimentary Matrix

Psilomelane (Black Hematite/Manganese Ore)

Barium Manganese Oxide (Formula: BaMn9O18(OH)4)

Red Sandstone

Arenite (primarily Quartz SiO2 with Hematite Fe2O3 cement)