Man Made Object (Metal Alloy)

Quartz

Quartz (SiO₂ - Silicon Dioxide)

Brecciated jasper, possibly rainforest jasper

Jasper: microcrystalline to cryptocrystalline quartz, SiO₂, commonly containing hematite, goethite, chlorite, epidote, and other iron- and manganese-bearing minerals

Fluorite (Purple Fluorite in Matrix)

Fluorite (Calcium Fluoride, CaF2)

Pale granite pebble (tentative identification)

Granite; a coarse-grained felsic intrusive igneous rock composed primarily of quartz and feldspar, with minor mica or amphibole

Quartzite (Sugar Quartz)

Quartzite (primarily SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Polished white chalcedony or milky quartz pebble

Chalcedony, microcrystalline quartz (SiO₂), possibly with iron-oxide staining or a minor mineral inclusion

Agate (or Chalcedony)

SiO2 (Silicon Dioxide) - a cryptocrystalline variety of quartz

White calcite (likely tumbled calcite or marble fragment)

Calcite, calcium carbonate (CaCO₃); if the specimen is granular and rock-like, it may be marble, a calcite-rich metamorphic rock

Moss Agate

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

Dark mafic rock, likely basalt

Basalt (fine-grained assemblage chiefly plagioclase and pyroxene, commonly with olivine and iron oxides)

Dark igneous rock, likely basalt

Basalt; chiefly plagioclase feldspar, pyroxene, and possibly olivine

Pink Granite (River Pebble)

Felsic intrusive igneous rock (consisting of Quartz, Orthoclase Feldspar, and Plagioclase)

Granite

Granite (Felsic Plutonic Rock)

Limestone

Calcium Carbonate (CaCO3)

Granite

Granitoid

Sandstone

Arenite (typically composed of SiO2)

Limestone

Calcium Carbonate (CaCO3)

Amethyst

SiO2 (Silicon Dioxide) - a variety of Quartz

Rose Quartz

Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Likely basalt or vesicular volcanic rock

Basalt, possibly scoriaceous basalt; exact identification is uncertain from the photograph

Red Jasper

Silicon dioxide (Microcrystalline Quartz, SiO2)

Granite

Granite (felsic intrusive igneous rock)

Granite

Granite (composed primarily of Quartz, Feldspar, and Mica/Amphibole)

Blue Apatite

Fluorapatite (Ca5(PO4)3F)

Granite

Phaneritic Igneous Rock (Granite)

Limestone (specifically Travertine or Tufa)

Calcium Carbonate (CaCO3)

Granite

Course-grained intrusive igneous rock

Sandstone Pebble

Arenite (primarily SiO2)

Limestone

Calcium Carbonate (CaCO3)

Sandstone (with potential mineral inclusions)

Clastic sedimentary rock (primarily Quartz, SiO2)

Limestone

Calcium Carbonate (CaCO3)

Limestone

Calcium Carbonate (CaCO3)

Granite River Rock

Phaneritic Felsic Igneous Rock (Granite)

Turquoise

Turquoise (Hydrated copper aluminum phosphate, CuAl6(PO4)4(OH)8·4H2O)

Rose Quartz

Silicon Dioxide (SiO2) with trace impurities of Titanium, Manganese, or Iron

Tumbled milky quartz

Quartz (silicon dioxide, SiO₂)

Arsenopyrite with Quartz

Arsenopyrite (FeAsS)

Basalt

Basalt (Mafic volcanic rock)

Rutilated Quartz

Quartz with Rutile Inclusions (SiO2 with TiO2 inclusions)

Granite

Granite (a felsic intrusive igneous rock)

Banded Iron Formation

Banded Iron Formation (BIF)