Igneous Or Metamorphic

Blue Apatite

Apatite-(CaF), Ca5(PO4)3F

Peach Moonstone

Orthoclase Feldspar (KAlSi3O8)

Smoky Quartz

Silicon Dioxide (SiO2)

Blue Sapphire

Corundum (Al2O3)

Quartz Vein in Gneiss/Granite

Silicon Dioxide (SiO2) in Feldspar-Quartz Gneiss host rock

Small pale-yellow stone, likely quartz or quartz-rich pebble

Unidentified silica-rich specimen; possibly quartz (SiO₂)

Weathered quartz-rich pebble

Quartz-bearing granitoid or quartzite; exact identification is uncertain from the image

Orange Quartz

Crystalline Silicon Dioxide (SiO2) with iron oxide inclusions

Citrine Quartz

Silicon Dioxide (SiO2) with iron impurities

Smoky Quartz

Smoky Quartz (Silicon Dioxide - SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Likely dark rounded pebbles

Indeterminate; possibly basalt or a dark mafic mineral such as hornblende/biotite

Quartz Crystal Cluster on Matrix

Silicon Dioxide (SiO2)

Smoky Quartz

Silicon dioxide with aluminum impurities (SiO2)

Milky quartz

Quartz (silicon dioxide, SiO₂)

Clear quartz crystal

Quartz (silicon dioxide, SiO₂)

Citrine

Silicon Dioxide (SiO2) with iron impurities

Sunstone

Oligoclase or Andesine (Feldspar Group), (Ca,Na)((Al,Si)4O8)

Smoky Quartz

Silicon Dioxide (SiO2) with aluminum impurities

Likely polished bronzite or serpentine-rich rock

Probable bronzite, an iron-bearing orthopyroxene (Mg,Fe)SiO₃; exact identification requires testing

Sapphire

Corundum (Al2O3)

Small pink quartz pebble

Quartz, SiO₂; possibly rose quartz or pale chalcedony

Quartz Pebble

Silicon Dioxide (SiO2)

Rounded pale pebble, likely quartz-rich stone

Indeterminate; possibly quartzite, quartz-bearing granite, or calcite-rich limestone

Milky quartz (rough quartz specimen)

Quartz, silicon dioxide (SiO₂)

Quartz with Iron Stains

Quartz (SiO2) with iron oxide/hydroxide staining

Red synthetic corundum (ruby-colored lab-grown sapphire)

Corundum, aluminum oxide (Al₂O₃), likely synthetic and chromium-colored

Black Tourmaline

Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)

Blue Apatite

Apatite (Calcium Phosphate) - Ca5(PO4)3(F,Cl,OH)

Rounded quartz-rich pebble, possibly granite or granitic gneiss

Granite/granitic rock; chiefly quartz (SiO₂), feldspar, and minor mica or mafic minerals

Yellow faceted gemstone, likely citrine or yellow sapphire

Uncertain from image; citrine is quartz (SiO₂), while yellow sapphire is corundum (Al₂O₃)

Polished yellow gemstone fragments, likely citrine or yellow sapphire

Uncertain from image; likely quartz (SiO₂) if citrine, or corundum (Al₂O₃) if yellow sapphire

Polished pink feldspar pebble

Microcline or orthoclase feldspar, KAlSi₃O₈, possibly with quartz or mica inclusions

Rounded reddish-brown river pebble

Indeterminate weathered silicate rock, possibly granite, rhyolite, or iron-stained quartzite

Milky quartz

Quartz, silicon dioxide (SiO₂)

Citrine

Silicon dioxide (SiO2)

Moonstone (Grey)

Feldspar (variety Orthoclase/Adularia) with the formula (K,Na)AlSi3O8

Amethyst

Silicon Dioxide (SiO2) containing iron impurities and irradiation

Milky Quartz with Iron Staining

Silicon Dioxide (SiO2) with Hematite/Limonite

Multi-Gemstone Quartz Bracelet (Amethyst, Aventurine, Rose Quartz, Clear Quartz)

Silicon Dioxide (SiO2) mixture

Milky quartz

Quartz (silicon dioxide, SiO₂)

Yellow Calcite

Calcium Carbonate (CaCO3)