Man Made Material

Banded Chert (Agate-like Flint)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Lepidolite

K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2 (Lepidolite - Lithium-rich Mica)

Likely tumbled quartz/chalcedony

Quartz (SiO₂), possibly milky quartz or pale chalcedony

Turquoise, Pearl, and Coral Necklace

CuAl6(PO4)4(OH)8·4H2O (Turquoise) / CaCO3 (Pearl and Coral)

Quartzite

Quartzite (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood

Silicified wood (Quartz, Chalcedony, or Opal)

Greenstone (likely serpentinite or chlorite-rich metamorphic rock)

Probable serpentinite/chlorite schist; commonly dominated by serpentine-group minerals, chlorite, talc, and magnetite

Picture Jasper

Silicon Dioxide (SiO2) with impurities

Red Sandstone

Arenite (primarily Quartz with Iron Oxide coating)

Quartz Grain

Silicon Dioxide (SiO2)

Dream Amethyst (Chevron Amethyst)

Silicon Dioxide with inclusions (SiO2)

Small quartz-rich pebble

Quartz (SiO₂), possibly quartzite or weathered granite fragment

Weathered sandstone or siltstone

Clastic sedimentary rock, chiefly quartz and feldspar grains cemented by clay, silica, or iron oxides

Vesicular basalt (weathered lava rock)

Basalt; primarily plagioclase feldspar, pyroxene, and commonly olivine (mafic volcanic rock)

Weathered iron-rich rock, possibly limonite-bearing sandstone or laterite

Limonite/goethite-rich ferruginous rock; exact identification requires testing

Weathered quartz-bearing rock, possibly sandstone or quartzite

Provisional: quartzite (mostly SiO₂); could alternatively be iron-stained quartz sandstone

Chalcedony in Matrix (likely Agatized Coral or Chert)

Silicon Dioxide (SiO2)

Polished tiger iron

Tiger iron; interlayered hematite, jasper, and crocidolite-quartz (often riebeckite)

Petrified Wood

Silicified Wood (SiO2)

Serpentinite (often containing Jadeite/Nephrite)

Antigorite-rich Serpentine Rock, (Mg, Fe)3Si2O5(OH)4

Milky Quartz

Quartz (Silicon Dioxide - SiO2)

Tree Agate

Silicon Dioxide (SiO2) with inclusions of manganese and iron oxides

Pink Quartz (Rose Quartz)

Silicon Dioxide (SiO2)

Iridescent schist or phyllite

Micaceous quartz-rich schist/phyllite, likely containing muscovite or chlorite

White quartz in dark matrix (likely quartz-bearing breccia or polished composite specimen)

Quartz, SiO₂, in an unidentified dark silicate matrix

Weathered quartz-rich rock, likely quartzite or quartz vein

Quartzite; predominantly quartz (SiO₂), possibly iron-oxide stained

Iron-stained chert or siliceous pebble

Microcrystalline quartz (SiO₂), likely ferruginous chert

Quartz-rich rock fragment

Microcrystalline quartz (SiO₂), possibly chalcedony or quartz-bearing breccia

Likely dark green-gray metamorphic pebble

Indeterminate; possibly chlorite schist, serpentinite, or amphibolite

Weathered limestone

Calcite-rich limestone (CaCO₃), possibly fossiliferous

Quartz-rich hydrothermal ore rock, likely gold-bearing quartz vein

Milky quartz (SiO₂) with iron-oxide staining and probable sulfide minerals; host rock may be schist or altered granite

Iron-stained quartz-bearing rock

Quartz (SiO₂), likely in a limonite/goethite-rich matrix

Tufa (Vesicular Limestone)

Tufa (form of Calcium Carbonate, CaCO3)

Milky Quartz Geode Fragment

Silicon Dioxide (SiO2)

Banded sandstone pebble

Lithic or quartz-rich sandstone; exact composition requires testing

Sandstone

Sedimentary Rock (Quartz Arenite)

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

Quartzite

Metamorphic Quartzite

Limestone

Sedimentary Rock (Primarily Calcium Carbonate, CaCO3)

Quartzite Pebble

Quartzite

Quartzite

Metamorphic Quartzite (SiO2)