All rocks & minerals

Magnetite (in matrix)

Magnetite (Fe3O4)

Quartz Pebble

Silicon Dioxide (SiO2)

Basalt with Epidote

Mafic volcanic rock with Epidote (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))

Granite

Granite (Phaneritic intrusive igneous rock)

Chert (Jasper/Common Chert Pebble)

Microcrystalline Quartz (SiO2)

Granite Pebble

Granite (Phaneritic intrusive igneous rock)

Chert (Iron-stained)

Silicon Dioxide (SiO2)

Granite Pebble

Granite (composed primarily of Quartz: SiO2, Feldspar: KAlSi3O8, and Mica: K(Mg,Fe)3AlSi3O10(OH)2)

Scoria

Scoriaceous Basalt

Quartz pebble

Silicon Dioxide (SiO2)

Gray Granite

Granite (Phaneritic igneous rock)

Quartz chunk

Silicon dioxide (SiO2)

Limestone

Calcium Carbonate (CaCO3)

Basalt

Basalt

Dalmatian Jasper

Peralkaline Quartz-Feldspar Rock with Arfvedsonite

Quartz (Milky/Clear variety)

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Quartz pebble

Silicon dioxide (SiO2)

Quartz (Small Fragment)

Silicon Dioxide (SiO2)

Diamond (Uncut/Rough)

Carbon (C)

Pumice

Pumice (Amorphous volcanic glass)

Anthracite Coal

Anthracite

Quartz Pebble

Silicon Dioxide (SiO2)

Chert (with Quartz)

Microcrystalline Quartz (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Quartz (Small Fragment)

Silicon Dioxide (SiO2)

Milky Quartz Pebble

Silicon Dioxide (SiO2)

Quartz pebble

Silicon Dioxide (SiO2)

Amazonite

Microcline (KAlSi3O8)

Quartz fragment

Silicon Dioxide (SiO2)

Quartz (small fragment)

Silicon Dioxide (SiO2)

Granitic Gravel

Granite (Quartz, Feldspar, and Mica mixture)

Quartz (Milky variant)

Silicon Dioxide (SiO2)

Quartz / Common Gravel

Silicon Dioxide (SiO2)

Chert (and Flint)

Silicon Dioxide (SiO2)

Banded Rhyolite (or Gray Shale pebble)

Rhyolite (SiO2 with minor impurities)

Quartzite

Quartzite (primarily SiO2)

Quartz (Gravel)

Silicon Dioxide (SiO2)

Chert (Flint)

Chert (SiO2)

Chert (Iron-stained)

Microcrystalline quartz (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)