Antropogenic (Man Made Glass Byproduct)

Weathered granite or granodiorite

Coarse-grained intrusive felsic igneous rock; chiefly quartz, plagioclase feldspar, potassium feldspar, and dark biotite/hornblende

Quartz

Silicon Dioxide (SiO2)

Honey-colored chalcedony (possibly yellow/orange agate or carnelian)

Chalcedony, a microcrystalline variety of quartz; SiO₂. The color may result from iron-oxide inclusions. Exact identification is uncertain from a photograph alone.

Rhinestone

Artificial Glass/Crystal

Snowflake Obsidian

Volcanic Glass (spherulitic Obsidian) - SiO2 (with Cristobalite inclusions)

Granite / Pegmatite with Quartz Vein

Granite (composed mainly of Quartz SiO2, Potassium Feldspar KAlSi3O8, and Plagioclase)

Serpentine Schist with Quartz Vein

Serpentine Schist (a type of Metamorphic rock). The white band is likely Quartz (SiO2).

Milky quartz (likely quartz vein fragment)

Quartz, silicon dioxide (SiO₂)

Tumbled carnelian agate

Cryptocrystalline chalcedony (SiO₂), an iron-colored variety of agate

Granite

Granite (composed primarily of silica-rich minerals like quartz and feldspar)

Limestone

Calcium Carbonate (CaCO3)

Granite

Plutonic felsic igneous rock

Vesicular volcanic rock, likely pumice

Pumice; highly vesicular volcanic glass, commonly rhyolitic to dacitic in composition

Vesicular basalt (probable)

Basalt, mainly plagioclase feldspar and pyroxene, with possible olivine and iron oxides

Mixed tumbled stone collection

Assorted minerals, likely including quartz, jasper, agate, and possibly obsidian or hematite

Weathered quartz-rich pebble (tentative)

Likely quartz/chalcedony, SiO₂, possibly iron-stained

Water-worn brown chert or jasper pebble

Microcrystalline quartz (SiO₂), likely ferruginous chert/jasper

Weathered quartz-rich rock, likely milky quartz/quartzite

Quartz (SiO₂), possibly quartzite with minor iron-oxide staining

Basalt (Lava Rock) and Dyed Glass/Quartz

Scoria (Vesicular Basalt)

Vesicular basalt (probable)

Basalt; chiefly plagioclase feldspar, clinopyroxene, and iron-rich minerals, with vesicles possibly lined by zeolites or calcite

Dark igneous rock, likely basalt

Basalt; chiefly plagioclase feldspar, pyroxene, and possibly olivine

Quartz vein in weathered host rock

Milky quartz (SiO₂), likely in a granitic or metamorphic matrix

Weathered basalt (likely vesicular basalt)

Basalt; primarily plagioclase feldspar, pyroxene, and commonly olivine

Pink granite (weathered, rounded cobble)

Granite; predominantly quartz, potassium feldspar, plagioclase, and mica/amphibole

Weathered granite or granitic pebble

Granite; chiefly quartz, alkali feldspar, plagioclase, and minor mica/amphibole

Tumbled yellow jasper or petrified wood fragment

Microcrystalline quartz (chalcedony), SiO₂, possibly iron-oxide-bearing jasper

Granite

Coarse-grained felsic intrusive igneous rock; primarily quartz, alkali feldspar, plagioclase, and biotite/hornblende

Small quartz-rich pebble

Quartz (SiO₂), possibly quartzite or weathered granite fragment

Granite River Cobble

Phaneritic Felsic Igneous Rock (Granite)

Carnelian

Carnelian (a variety of Chalcedony, SiO2)

Rhinestone (or glass crystal)

Silicon dioxide (if glass) / Various

Amber (and Citrine Quartz)

Succinite (Amber) and Silicon Dioxide (SiO2)

Red Coral (Precious Coral)

Corallium rubrum (Calcium Carbonate, CaCO3)

Quartzite

Quartzite (primarily SiO2)

Snowflake Obsidian

Obsidian (volcanic glass) with Cristobalite inclusions

Quartz (clear quartz/crystal quartz)

Quartz, silicon dioxide (SiO₂), trigonal crystal system

Tumbled quartz (likely rose or milky quartz)

Quartz, silicon dioxide (SiO₂)

Brecciated jasper, possibly rainforest jasper

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

Tumbled amethyst with possible lepidolite/colored quartz companion

Amethyst, purple quartz (SiO₂), likely with iron-related color centers

Granite

Felsic intrusive igneous rock

Granite

Felsic Plutonic Rock

Granite

Felsic Intrusive Igneous Rock