Metamorphic Or Sedimentary (With Staining)

Milky quartz

Quartz (silicon dioxide, SiO₂)

Quartz-veined metamorphic rock, likely schist or phyllite

Quartz-bearing mica schist/phyllite; exact identification requires closer examination

Weathered quartz-rich rock, possibly quartzite or altered granite

Quartz-dominant silicate rock; exact identification requires a fresh surface and tests

Iron-rich quartzite or weathered ironstone

Quartzite, chiefly SiO₂, with iron-oxide minerals such as hematite/goethite

Weathered metamorphic rock, likely gneiss or schist

Indeterminate foliated silicate rock; commonly quartz–feldspar–mica assemblage

Weathered iron-rich stone, possibly chert or quartzite

Indeterminate; likely silica-rich rock with iron-oxide staining (SiO₂-dominant)

Quartzite River Rock (with Limonite staining)

Quartzite (SiO2)

Quartz with Iron Oxide Stain

Silicon Dioxide (SiO2) with Hematite/Limonite coatings

Kyanite-rich schist (probable)

Kyanite-bearing quartz–mica schist; kyanite, Al₂SiO₅

Tumbled yellow quartzite or jasper

Quartzite, primarily microcrystalline SiO₂; exact identification requires testing

Feldspar (Plagioclase / Potassium Feldspar)

Feldspar Group (KAlSi3O8 - NaAlSi3O8 - CaAl2Si2O8)

Decorative polished pebbles

Likely mixed quartz-rich lithologies, including quartzite, jasper, and/or basalt

Weathered sulfide-bearing metamorphic rock (likely pyrite- or chalcopyrite-rich schist)

Quartz–mica schist with iron sulfides; possible pyrite (FeS₂) and chalcopyrite (CuFeS₂)

Iron-stained Quartzite / Chert

Silicon Dioxide (SiO2) with Hematite/Limonite impurities

Milky quartz / quartz vein fragment

Quartz, silicon dioxide (SiO₂)

Epidote–garnet schist (probable)

Epidote + garnet + quartz/feldspar mica schist; garnet may be almandine–grossular series

Weathered quartz-rich rock, possibly quartzite or silicified sandstone

Quartzite (mostly SiO₂), with possible iron-oxide staining and minor feldspar/mica

Quartz-bearing rock or quartz-rich mineral specimen

Quartz, silicon dioxide (SiO₂); exact host rock is uncertain from the image

Weathered granitic gneiss

Foliated quartz–feldspar–mica gneiss, likely with biotite and amphibole

Rounded quartz pebble (tentative)

Quartz, silicon dioxide (SiO₂)

Dark gray rock fragment, likely basalt

Basalt; chiefly plagioclase feldspar and pyroxene, commonly with minor olivine and magnetite

Dark gray volcanic rock, probably andesite or basalt

Fine-grained mafic–intermediate volcanic rock; likely basalt (plagioclase ± pyroxene), possibly andesite

Gneiss

Metamorphic Gneiss (High-grade regional metamorphism)

Quartz-bearing metamorphic rock, likely quartzite or hornfels

Quartz (SiO₂) in a fine-grained silicate matrix; exact rock identification requires testing

Weathered quartz-rich metamorphic rock, likely quartzite

Quartzite, predominantly crystalline SiO₂, possibly micaceous or feldspathic

Raw quartz crystal

Quartz (silicon dioxide, SiO₂), likely milky or iron-stained quartz

Polished/tumbled iron-rich jasper (likely brecciated jasper)

Jasper, microcrystalline quartz (SiO₂) colored chiefly by iron oxides/hydroxides

Polished malachite

Malachite, Cu₂CO₃(OH)₂

Iron-rich quartzite or weathered ironstone pebble

Quartzite, chiefly SiO₂, with iron-oxide minerals (hematite/goethite)

Mixed rock and mineral specimen collection

Mostly undetermined from the photograph; apparent quartz-rich rocks, sandstone, granite/gneiss, and possibly iron-oxide-bearing specimens

Weathered quartz-rich rock, possibly quartzite or chert

Quartz (SiO₂), likely in a quartzite matrix; exact identification is uncertain from the image

Iron-stained quartz-rich rock, likely quartzite or silicified sandstone

Quartz (SiO₂) with iron-oxide minerals, chiefly hematite/goethite; exact host-rock identification is uncertain from the photograph

River Pebble (Quartzite or Chert)

Silicon Dioxide (SiO2)

Banded gneiss or banded metamorphic rock

Gneiss, likely quartz–feldspar–biotite gneiss

Tumbled tan quartzite or chert pebble

Quartzite, predominantly microcrystalline quartz (SiO₂); possibly chert, also SiO₂

Weathered quartz-rich rock, possibly quartzite or granite fragment

Quartzite (SiO₂-dominant) or altered granitoid; uncertain from image

Weathered jasper or iron-stained quartzite

Silicified quartz-rich rock, primarily microcrystalline quartz (SiO₂) with iron-oxide/hydroxide staining

Mica Schist with Biotite or Muscovite

Metamorphic rock rich in sheet silicates

Milky Quartz Vein in Host Rock

Silicon Dioxide (SiO2)

Clear Quartz Cluster

Crystalline Silicon Dioxide (SiO2)

Banded gneiss (likely biotite-bearing)

Gneiss; quartz–feldspar–mica assemblage, with possible iron-oxide staining

Muscovite mica schist

Muscovite-rich schist; predominantly muscovite mica (KAl₂(AlSi₃O₁₀)(OH)₂) with quartz and minor iron oxides