Mineral, Part Of A Rock

Basalt Pebble

Basalt (Aphanitic Mafic Igneous Rock)

Weathered mica-rich rock fragment

Likely biotite granite or granitic gneiss; exact identification is uncertain from the photograph

Granite

Phaneritic Felsic Igneous Rock

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Druzy Quartz on Chert/Siltstone

Silicon Dioxide (SiO2) on Microcrystalline Silica/Siltstone matrix

Granite Pebble (Salt and Pepper Granite)

Phaneritic Felsic Igneous Rock (primarily Quartz, Feldspar, and Biotite/Amphibole)

Basalt Gravel

Aphanitic Mafic Igneous Rock

Basalt (Vesicular)

Extrusive mafic igneous rock

Basalt

Basalt (Mafic Volcanic Rock)

Granite

Granite

Likely rough pink feldspar or rose quartz

Most likely microcline feldspar (KAlSi₃O₈) or rose quartz (SiO₂)

Quartz (Smoky/Milky variant)

Silicon Dioxide (SiO2)

Polished dendritic agate pendant

Microcrystalline quartz (SiO₂), with dark manganese- or iron-oxide dendrites

Weathered sandstone or iron-rich sedimentary rock fragments

Quartz-rich sandstone, locally ferruginous; exact identification requires testing

Quartz (Milky or Cloudy)

Silicon Dioxide (SiO2)

Parian marble sculpture fragment

Marble, predominantly calcite (CaCO₃), likely a fine-grained Greek island marble

White calcite fragment (likely limestone or marble)

Calcite, calcium carbonate (CaCO₃); exact host rock is uncertain from the image

Quartz (in a rock matrix)

Quartz (SiO2)

Granite Cobble

Granite (Felsic Plutonic Rock)

Rounded river pebble, likely quartz-rich sandstone or quartzite

Composition and exact rock type cannot be determined from the photo; likely quartz (SiO₂) with minor feldspar and rock fragments

Gabbro (potentially weathered)

Mafic Plutonic Rock (Gabbro/Diabase)

Granite

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

Yellow Quartzite (River Pebble)

Crystalline Quartz (SiO2)

Quartzite (River Pebble)

Metamorphic Quartzite (SiO2)

Garnet Schist

Almandine Garnet in Mica Schist

Quartz Sand/Gravel

Silicon Dioxide (SiO2)

Gabbro

Phaneritic Basic Igneous Rock (Gabbro)

Fossilized Shark Tooth (Fragment) in Matrix

Elasmobranchii (subclass)

Basalt

Extrusive mafic rock (Basalt)

Granite Pebble

Granite (Felsic Plutonic Rock)

River Cobble (likely Basalt or Chert)

Basalt (Mafic volcanic rock)

Granite

Phaneritic igneous rock consisting of Quartz, Potassium Feldspar, and Plagioclase

Granite

Phaneritic Igneous Rock (composed primarily of Quartz, Alkali Feldspar, and Plagioclase)

Tumbled chalcedony pendant (likely agate)

Chalcedony, microcrystalline quartz (SiO₂); the pale bands suggest agate

Quartz Geode (partially formed)

Silicon Dioxide (SiO2)

River Pebble

Polished Quartzite or Mixed Lithology

Polished granite pebble

Granite, commonly quartz–feldspar–mica aggregate

Red sandstone

Quartz-rich siliciclastic sandstone, likely ferruginous arkose or litharenite

Quartz pebble

Silicon dioxide (SiO2)

Basalt

Mafic Igneous Rock (primarily Plagioclase and Pyroxene)

Granite

Phaneritic Plutonic Felsic Rock (SiO2 > 69%)

Granite

Phaneritic intrusive igneous rock (Granite)