All rocks & minerals

Iron-stained quartz vein fragment

Quartz (SiO₂) with iron-oxide staining, likely hematite and/or goethite

Weathered fossiliferous limestone pebble

Fossiliferous limestone, composed chiefly of calcite (CaCO₃)

Speckled granite

Granite, chiefly quartz, feldspar, and dark biotite or amphibole

Mixed collection of polished geological specimens; central specimen is likely diorite

Diorite (probable; plagioclase feldspar and dark amphibole/biotite)

Quartz-rich rock fragment

Likely iron-stained milky quartz, predominantly silicon dioxide (SiO₂); precise rock identification is uncertain from the image

Weathered greenstone (altered mafic rock)

Greenschist-facies metabasalt; typically chlorite, actinolite, epidote, and albite

Quartzite

Quartzite, composed predominantly of quartz (SiO₂)

Quartz-rich sandstone

Quartz arenite (tentative; quartz-rich sandstone)

Fossilized bone, possibly a large limb bone

Fossil bone composed chiefly of bioapatite (hydroxyapatite); exact animal and identification are indeterminate from the photo

Rounded river pebble, likely quartzite

Quartzite (predominantly recrystallized quartz, SiO₂); identification is provisional from the image

Rounded tan stone, likely limestone

Probably micritic limestone (calcite, CaCO₃); identification is uncertain from the image alone

Rounded sandstone pebble

Quartz-rich sandstone; exact composition cannot be confirmed from the image

Iron-oxide-stained sandstone (likely ferruginous sandstone)

Quartz-rich sandstone cemented or stained by iron oxides, chiefly hematite (Fe₂O₃) and possibly goethite (FeO(OH))

Smoky quartz vein fragment

Quartz, SiO₂ (likely smoky quartz)

Quartz-rich pegmatite

Granitic pegmatite, composed mainly of quartz (SiO₂) with likely feldspar and mica

Porphyritic volcanic rock (likely andesite)

Porphyritic andesite; exact identification requires closer examination

Milky quartz vein in iron-stained host rock

Quartz, SiO₂; host rock is not identifiable from the image

Polished green aventurine (likely)

Aventurine quartz, SiO₂, colored by fuchsite or other inclusions

Ironstone concretion (likely hematite-rich)

Iron-oxide-cemented sediment, chiefly hematite (Fe₂O₃) and/or goethite (FeO(OH))

Polished green-gray stone, possibly serpentine

Likely serpentine-group rock, composed mainly of serpentine minerals; identification is uncertain from the photo

Iron-stained conglomerate or breccia

Ferruginous clastic rock; likely quartz-rich sandstone with angular to rounded lithic clasts cemented by iron oxides

Iron-stained quartz with reddish iron-oxide coating

Quartz (SiO₂), likely colored by hematite (Fe₂O₃) and/or goethite (FeO(OH))

Cavansite on matrix

Cavansite, Ca(VO)Si₄O₁₀·4H₂O, on likely stilbite or another zeolite matrix

Iron-stained porphyritic volcanic rock (possibly altered tuff)

Likely porphyritic andesite or volcanic tuff; exact identification requires examination of a fresh surface

Cavansite on matrix

Cavansite, Ca(VO)Si₄O₁₀·4H₂O

Iron-rich laterite or weathered ironstone fragment

Lateritic ironstone, composed mainly of iron oxides/hydroxides such as goethite and hematite

Green-and-white feldspar-bearing stone, possibly amazonite

Likely microcline feldspar (KAlSi₃O₈), with pale quartz or feldspar; identification is uncertain from the photo

Polished garnet-bearing metamorphic rock (likely garnet schist)

Garnet schist; commonly garnet (often almandine, Fe₃Al₂(SiO₄)₃) in mica-rich rock

Greenstone pebble

Greenstone (metamorphosed mafic rock, commonly altered basalt); exact identification requires testing

Pumice (likely)

Pumice, vesicular volcanic glass; typically silica-rich rhyolitic to dacitic composition

Milky quartz with iron staining

Quartz, silicon dioxide (SiO₂)

Weathered granite

Granite, a coarse-grained intrusive felsic igneous rock composed mainly of quartz, feldspar, and mica

Milky quartz vein fragment

Quartz, silicon dioxide (SiO₂)

Likely garnet-bearing rock

Garnet-rich schist or garnetiferous metamorphic rock; garnet is commonly almandine, Fe₃Al₂(SiO₄)₃

Polished greenstone pebble

Likely chlorite- or actinolite-bearing greenstone (metamorphosed mafic rock)

Iron-stained quartz (likely milky quartz)

Quartz, silicon dioxide (SiO₂), colored by iron-oxide staining

Milky quartz with iron-oxide staining

Quartz (SiO₂), likely massive to crystalline vein quartz

Iron-stained quartz-rich rock

Quartz-rich vein rock, possibly iron-oxide-stained quartzite or brecciated quartz

Iron-stained quartz-rich rock (possibly iron-stained quartzite)

Quartz-rich silicate rock; exact identification is uncertain from the image

Iron-stained quartz-rich rock (likely ferruginous quartzite)

Quartz (SiO₂) with iron oxides, chiefly hematite/goethite; exact rock type cannot be confirmed from the photo

Milky quartz

Quartz (SiO₂), typically massive rather than visibly crystalline

Carnelian (orange chalcedony) pebble

Chalcedony, microcrystalline quartz (SiO₂), colored by iron oxides