Mineraloid

Tumbled purple rock, likely lepidolite-bearing mica schist

Lepidolite-rich mica schist; lepidolite K(Li,Al)₃(Si,Al)₄O₁₀(F,OH)₂, possibly mixed with quartz and feldspar

Scoria (vesicular volcanic rock)

Basaltic to andesitic scoria; chiefly plagioclase, pyroxene, and volcanic glass

Green aventurine (likely)

Quartz, SiO₂, with green fuchsite or other mica inclusions; identification from the image is uncertain

Likely amphibolite (hornblende gneiss or mafic metamorphic rock)

Amphibolite, chiefly hornblende amphibole and plagioclase feldspar, with possible quartz, biotite, or epidote

Likely gabbro or basaltic rock fragments

Mafic igneous rock, chiefly plagioclase feldspar and pyroxene; exact identification requires testing

Galena-bearing ore

Galena (lead sulfide, PbS), likely with sphalerite and sulfide gangue

Graphite-rich metamorphic rock (likely graphite schist)

Graphite schist; predominantly graphitic carbon (C) with mica and quartz

Polished brecciated jasper

Silica-rich microcrystalline quartz/chalcedony (SiO₂), with iron-oxide and other mineral inclusions

Small brown-gray mineral fragment

Indeterminate; possibly weathered quartz-, feldspar-, or iron-oxide-bearing rock

Diorite Gneiss

Foliated Diorite Gneiss

Greenstone pebble (identification uncertain from photo)

Greenstone, typically metamorphosed mafic rock composed of chlorite, actinolite, and epidote

Yellow serpentine (likely serpentine-rich rock)

Serpentinite; chiefly serpentine-group minerals, such as antigorite, lizardite, and chrysotile

Greenstone, likely serpentinite

Serpentinite; predominantly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, chlorite, and talc

Tumbled gray chalcedony or quartz pebble

Microcrystalline quartz (SiO₂), possibly gray chalcedony

Tumbled gabbro (likely larvikite or related mafic rock)

Coarse-grained mafic intrusive rock; chiefly plagioclase feldspar, pyroxene, and minor biotite/amphibole

Weathered quartz-rich rock, possibly granite or quartzite

Indeterminate; likely quartz–feldspar aggregate, potentially altered granite

Tumbled Slate or Basalt Pebble

Metamorphic fine-grained rock / Slate or Phyllite

Weathered green metamorphic rock, possibly serpentinite or greenstone

Likely serpentinite (serpentine-group minerals) or chlorite/epidote-rich greenschist; exact identification requires testing

Dark gray fine-grained stone, likely basalt

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

Weathered metal-rich igneous rock, likely basalt or komatiitic peridotite

Probable altered mafic–ultramafic rock containing pyroxene/amphibole, olivine, iron oxides, and possible metallic sulfides

Mica-rich pegmatitic granite

Granitic pegmatite, chiefly quartz, feldspar, and muscovite/biotite mica

Eclogite

Eclogite (Omphacite-Garnet rock)

Serpentine-bearing metamorphic rock (likely chromite/vesuvianite-bearing serpentinite)

Serpentinite, chiefly serpentine-group minerals [(Mg,Fe)₃Si₂O₅(OH)₄], with dark accessory minerals

Serpentinized ultramafic rock with magnesite

Serpentinite, chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), with likely magnesite (MgCO₃) and minor chromite/magnetite

Quartzite

Quartzite (primarily SiO2)

Granite

Phaneritic Felsic Igneous Rock

Granite

Phaneritic Felsic Igneous Rock

Granite

Phaneritic Felsic Igneous Rock

Drill Core Sample

Cylindrical Rock Core (Specific mineralogy varies by extraction site)

Dalmatian jasper (often sold as Dalmatian stone)

Quartz-bearing microgranular felsic rock, commonly an altered rhyolite or related volcanic rock with black aegirine/arfvedsonite-group inclusions

Manganese Dendrite on Siltstone

Manganese Oxide (pyrolusite or psilomelane) Dendrites

Pyrite Sun (Pyrite Dollar)

Iron Disulfide (FeS2)

Yellow chalcedony (likely dyed or heat-treated)

Microcrystalline quartz, SiO₂ (chalcedony)

Weathered rhyolitic tuff or altered volcanic rock

Felsic volcanic tuff, likely devitrified or hydrothermally altered

Granite-like rock

Felsic intrusive igneous rock, probably granitic or granodioritic

Mica Schist (with Golden/Biotite inclusions)

K(Mg,Fe)3AlSi3O10(F,OH)2 (Biotite), KAl2(AlSi3O10)(F,OH)2 (Muscovite)

Likely serpentinite

Serpentinite, composed mainly of serpentine-group minerals (such as antigorite or chrysotile)

Polished greenstone pebble (likely serpentine or chlorite-rich stone)

Serpentine-group minerals, commonly antigorite/lizardite; possible chlorite-rich metamorphic rock

Amygdaloidal basalt pebble

Vesicular basalt, locally calcite- or quartz-filled amygdales

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

Undetermined; likely iron oxides/hydroxides (goethite–hematite–limonite) in a silicate host

Granite

Granite (Plutonic Igneous Rock)

Granite

Granite (composed primarily of Quartz, Alkali Feldspar, and Plagioclase)