Mineral In A Matrix (Likely Quartz Or Feldspar)

Dyed druzy quartz geode

Quartz, silicon dioxide (SiO₂), likely artificially dyed

Granite (likely weathered, coarse-grained granite)

Granite, composed chiefly of quartz, feldspar, and mica

Pink granite

Felsic intrusive igneous rock; chiefly quartz, alkali feldspar, plagioclase, and dark biotite/hornblende

Uncertain polished mineral specimen

Indeterminate; possibly quartz or feldspar with iron-oxide staining

Mixed rounded river pebbles

Polymictic alluvial gravel; likely quartz/quartzite, chert, and weathered feldspathic rocks

Polished garnet-bearing metamorphic rock

Likely garnet mica schist or garnet-bearing gneiss; garnet is commonly almandine, Fe₃Al₂(SiO₄)₃

Likely granite pebble

Granite, a quartz–feldspar–mica intrusive igneous rock

Weathered quartz-rich metamorphic rock (probable gneiss or quartzite)

Biotite–quartz–feldspar gneiss, possibly micaceous quartzite

Pink granite

Granite, chiefly quartz–alkali feldspar–plagioclase with biotite/hornblende

Weathered granite or granitic pegmatite

Granite; primarily quartz (SiO₂), feldspar, and mica

Biotite-bearing granite or granitic gneiss

Granite/granitic gneiss, chiefly quartz, feldspar, and biotite mica, with possible epidote or chlorite alteration

Granite or granitic rock fragment

Granite, primarily quartz, feldspar, and mica; exact identification is uncertain from the photograph

Porphyry

Porphyritic Andesite or Rhyolite

Milky quartz with iron-stained matrix

Quartz (silicon dioxide, SiO₂)

Weathered quartz-rich rock, likely granite or granitic gneiss

Granite–gneissic felsic rock; chiefly quartz (SiO₂), feldspar, and minor mica/biotite

Milky quartz

Quartz (SiO₂), likely massive milky quartz

Weathered porphyritic volcanic rock

Likely altered andesite or rhyolite porphyry

Granite

Granite (composed mainly of quartz, alkali feldspar, and plagioclase)

Dalmatian Jasper (Dalmatian Stone)

Perthitic feldspar with Arfvedsonite inclusions

Biotite-bearing granite (possibly granodiorite)

Coarse crystalline quartz–feldspar–biotite rock; approximate composition: quartz SiO₂, feldspars, and biotite K(Mg,Fe)₃AlSi₃O₁₀(F,OH)₂

Weathered granitic rock

Granite, likely biotite granodiorite

Quartz-rich feldspar rock, possibly pegmatitic granite

Granite or granitic pegmatite; mainly quartz (SiO₂) and feldspar, with possible mica

Quartz-rich rock fragment

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

Pink feldspar-rich rock, likely rose quartz or pink granite fragment

Indeterminate from image; possible potassium feldspar (orthoclase, KAlSi₃O₈) or quartz (SiO₂)

Tumbled white feldspar (likely albite or orthoclase)

Feldspar-group tectosilicate; commonly albite NaAlSi₃O₈ or orthoclase KAlSi₃O₈

Porphyritic Basalt or Andesite

Porphyritic Basalt/Andesite

Amethyst cluster (quartz geode fragment)

Amethyst, purple variety of quartz; silicon dioxide (SiO₂) colored mainly by iron-related defects

Amethyst druzy cluster

Amethyst, purple quartz (SiO₂)

Pink-and-white quartz-rich rock, likely rose quartz-bearing pegmatite

Quartz (SiO₂) with pink microcline feldspar and possible albite/muscovite; likely granitic pegmatite

Weathered quartz-bearing rock, possibly druzy quartz or quartzite

Quartz (SiO₂), likely in a quartz-rich host rock; exact identification is uncertain from the photograph

Tumbled jasper or rhyolitic porphyry

Silicic volcanic rock, likely rhyolite (quartz- and feldspar-rich), possibly jasperized

Gneiss

Quartz–feldspar–mica gneiss

Granite Pebble

Phaneritic Felsic Igneous Rock (Granite)

Feldspar-Quartz Rock (likely Pegmatite or Granite)

Feldspar-Quartz composite rock (KAlSi3O8 - SiO2)

Weathered granitic rock

Granite or granodiorite; mainly quartz, feldspar, and mica/amphibole

Milky quartz pebble

Quartz, silicon dioxide (SiO₂)

Polished chrysoprase (likely)

Chalcedony, microcrystalline quartz (SiO₂), colored by nickel-bearing minerals

Rounded granite cobble

Granite; chiefly quartz, alkali feldspar, plagioclase, and biotite/hornblende

Granite pebble

Granite, chiefly quartz, feldspar, and mica

Weathered quartz-rich rock, likely granite or granitic pegmatite

Granite/pegmatite; chiefly quartz (SiO₂), feldspar, and minor mica or iron oxides

Rhyolitic porphyry (likely weathered volcanic rock)

Silica-rich volcanic rock, chiefly quartz and alkali feldspar in a fine-grained groundmass; possible iron-oxide staining

Fish Fossil in Limestone

Lycoptera (likely) in Micritic Limestone