Mixed (Igneous, Sedimentary, Metamorphic, And Minerals)

Glauconitic Sandstone

Glauconitic Sandstone (Quartz with Glauconite)

Quartz Pebble

Silicon Dioxide (SiO2)

Magnetic Sand Grain / Magnetite Pellet

Magnetite (Fe3O4)

Epidote in Quartz

Epidote (Ca2(Al2,Fe3+)3(SiO4)3(OH)) / Quartz (SiO2)

Quartz (Pebble)

Silicon Dioxide (SiO2)

Weathered granite or granitic gneiss

Granite; chiefly quartz, feldspar, and mica, with iron-oxide weathering

Feldspar-Quartz Rock (likely Pegmatite or Granite)

Feldspar-Quartz composite rock (KAlSi3O8 - SiO2)

Gneiss

Metamorphic Foliated Gneiss

Mixed collection of Quartz varieties, Chalcedony, and metamorphic pebbles

Mixed gemstones (primarily Silicon Dioxide - SiO2)

Apatite

Fluorapatite / Chlorapatite (Ca5(PO4)3(F,Cl,OH))

Quartz-rich rock fragment

Likely milky quartz with feldspar and possible mica; exact rock type is indeterminate from the image

Pyrite in Quartz Matrix

Iron Sulfide (FeS2) embedded in Silicon Dioxide (SiO2)

Sodalite

Sodium Aluminum Silicate Chloride (Na8(Al6Si6O24)Cl2)

Likely quartz-bearing mineral aggregate

Quartz (SiO₂), possibly mixed with mica or feldspar

Milky Quartz

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Beach cobbles, predominantly basalt with vesicular volcanic fragments

Basalt (mafic volcanic rock), with possible altered basalt and minor feldspar/quartz-bearing pebbles

Weathered volcanic rock fragment

Likely andesite or basaltic-andesite; exact identification requires fresh surface and testing

Mixed gemstone bead bracelet

Likely rose quartz, amethyst, and possibly rhodonite or lepidolite beads

Iron-rich concretion (likely limonite/goethite)

Limonite–goethite aggregate; commonly hydrated iron oxides, approximately FeO(OH)·nH₂O

Magnetite (Iron Ore)

Magnetite (Fe3O4)

Quartz Pebble

Silicon Dioxide (SiO2)

Gravel and Sediment Sample

Mixed clastic sediment

Clear Quartz (Faceted)

SiO2 - Silicon Dioxide

Tumbled purple-blue corundum, possibly sapphire

Corundum (Al₂O₃); blue-to-purple varieties are sapphire

Quartz

Silicon Dioxide (SiO2)

Granitic Quartz or Pegmatite

Quartz with Orthoclase Feldspar (SiO2 + KAlSi3O8)

Banded Metamorphic Rock

Gneiss or Schist

Banded gneiss (likely garnet-biotite or quartz-feldspar gneiss)

Gneiss; predominantly quartz (SiO₂), feldspar, and dark biotite/amphibole

Blue Quartz

Silicon Dioxide (SiO2) with inclusions

Blue Quartz

Silicon Dioxide (SiO2) with inclusions

Mixed sandstone and iron-rich sedimentary rock fragments

Quartz arenite/subarkose, with ferruginous cement and possible iron-oxide staining

Rounded, weathered rock (likely quartz-rich granite or gneiss)

Undetermined quartz–feldspar-rich rock; precise identification requires closer examination

Blue Apatite

Fluorapatite (Ca5(PO4)3(F,Cl,OH))

Feldspar (Granite Pegmatite matrix)

Potassium Feldspar (KAlSi3O8) / Quartz Mixture

Tumbled metallic sulfide mineral specimen, likely pyrite-bearing ore

Likely pyrite (FeS₂) with associated sulfides and host rock; exact identification requires testing

Weathered granite pebble

Granite, predominantly quartz–feldspar–mica aggregate

Banded gneiss

Gneiss, likely quartz–feldspar–mica gneiss

Quartz with Inclusions

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Magnetite (potentially Hematite)

Magnetite (Fe₃O₄)

Quartz-rich conglomeratic breccia

Polymictic clast-supported conglomerate/breccia, dominated by quartz and feldspar