Sedimentary Rock (Altered)

Pink Anthracite Coal (dyed)

Anthracite Coal (Artificially Colored)

Weathered red-and-green metamorphic rock

Probable epidote-amphibolite or altered schist; exact identification requires testing

Unidentified tan rock fragment

Indeterminate from photograph; possibly a carbonate rock such as limestone

Jasper

Microcrystalline Quartz (SiO2)

Weathered brown rock fragment

Indeterminate; possibly iron-stained sandstone, mudstone, or weathered limestone

Weathered sandstone or iron-stained sedimentary rock

Quartz-rich sandstone, likely limonitic/goethitic cement

Likely bituminous coal

Coal, predominantly carbon-rich organic matter; exact rank cannot be confirmed from the image

Likely bituminous coal

Coal, predominantly carbon-rich organic matter with variable maceral and mineral content

Altered volcanic rock, possibly andesite

Likely porphyritic andesite or dacite with secondary chlorite/epidote and quartz–calcite veins

Weathered porphyritic volcanic rock, likely andesite

Porphyritic andesite (tentative; plagioclase ± pyroxene/amphibole in a fine groundmass)

Likely bituminous coal

Coal, predominantly maceral-rich carbonaceous material (composition varies)

Likely bituminous coal

Coal, predominantly carbon-rich organic matter; rank and composition cannot be confirmed from the image

Weathered yellow-brown rock fragment

Indeterminate; possibly iron-stained sandstone or weathered limestone

Polished brecciated jasper

Jasper, an opaque microcrystalline variety of chalcedony (SiO₂), with iron-oxide staining

Weathered quartz-bearing rock, possibly calcite vein fragment

Indeterminate; likely quartz (SiO₂) with carbonate minerals such as calcite (CaCO₃)

Greenstone, likely altered basalt

Metabasalt (chlorite–actinolite–epidote assemblage), likely greenschist-facies greenstone

Likely mica-rich schist

Mica schist, probably muscovite- and/or biotite-bearing; exact identification requires closer examination

Likely mica-rich schist

Mica schist, composed mainly of muscovite and/or biotite with quartz; exact identification is uncertain from the photo.

Quartz-bearing dark rock, possibly hornfels or basalt

Probable quartz–feldspar rock; exact identification requires testing

Weathered brown stone, possibly chert or iron-stained limestone

Uncertain; likely microcrystalline quartz (SiO₂) chert or calcitic limestone (CaCO₃)

Likely weathered gray limestone or shale fragment

Calcite-rich carbonate rock (limestone), possibly calcareous shale

Jasper

Silicon Dioxide (Microcrystalline Quartz, SiO2)

Likely mica-rich metamorphic rock (schist)

Mica schist, probably containing muscovite and/or biotite with quartz and feldspar

Drill-core rock, likely foliated metamorphic rock

Indeterminate from the photograph; possibly slate, phyllite, or schist

Weathered, foliated metamorphic rock (likely schist or phyllite)

Probably mica-rich schist or phyllite; exact identification requires close examination of its grains and foliation

Weathered mica-rich rock fragment

Likely mica schist or phyllite; identification is uncertain from the image alone

Weathered iron-rich rock, possibly limonite-bearing basalt or ironstone

Uncertain; likely Fe-oxide/hydroxide–stained mafic rock (hematite Fe₂O₃, goethite FeO(OH), and silicates)

Red jasper in gray host rock (likely hematite-stained quartzite or rhyolite)

Jasper: microcrystalline quartz (SiO₂), with iron-oxide coloration; exact host uncertain from image

Mica-bearing metamorphic rock with a dark mica crystal

Likely schist or mica-rich gneiss; dark crystal appears to be biotite, though identification from the photo is uncertain

Rounded river pebble, likely weathered sandstone or volcanic rock

Indeterminate fine-grained lithic clast; possible sandstone (quartz-rich)

Mica-rich schist

Mica schist, likely quartz–mica schist (quartz with muscovite and/or biotite)

Likely bituminous coal

Coal, predominantly carbon-rich organic matter; exact rank cannot be confirmed visually

Red Jasper or Ferruginous Chert

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Uncertain green-brown mineral fragment

Possibly epidote, chlorite, or altered amphibole; exact identification requires testing

Weathered mafic rock, likely basalt

Basalt; primarily plagioclase feldspar, pyroxene, and minor olivine or iron oxides

Jasper (Banded Jasper / Chert)

Silicon Dioxide (SiO2 with iron oxide inclusions)

Polished brecciated jasper (likely ocean jasper or orbicular jasper)

Microcrystalline quartz/chalcedony (SiO₂) with iron-oxide and other mineral inclusions

Gneiss

Gneiss

Red Zebra Jasper

Silicon dioxide with hematite impurities (SiO2)

Rounded sandstone pebble

Quartz-rich sandstone, likely ferruginous or clay-rich

Likely mica schist

Mica-rich schist, probably muscovite–biotite schist

Weathered quartz-rich river stone

Chert or silicified limestone/quartzite; exact identification requires testing