Weathered iron-rich rock, possibly basalt or ironstone
Indeterminate; likely Fe-oxide-bearing basaltic rock (commonly magnetite/hematite in a silicate matrix)
igneous
Category
Mineraloid (Synthetic)
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Granite
Intrusive igneous rock composed mainly of quartz, alkali feldspar, and plagioclase
igneous
Gneiss (specifically a granitic gneiss cobble)
Gneiss (high-grade regional metamorphic rock)
metamorphic
Sapphire
Corundum (Al2O3)
mineral
Limonite with Quartz
FeO(OH)·nH2O (Limonite) with SiO2 (Quartz)
mineral
Granodiorite
Granodiorite (containing Plagioclase, Quartz, and Biotite)
igneous
Granitic Gneiss
Gneiss (High-grade metamorphic rock)
metamorphic
Granite
Phaneritic Plutonic Felsic Rock
igneous
Granite (Fine-grained)
Phaneritic Felsic Igneous Rock
igneous
Granite
Granite (Felsic Plutonic Rock)
igneous
Granite
Phaneritic Plutonic Igneous Rock (Granite)
igneous
Granite
Phaneritic Igneous Rock (composed of quartz, alkali feldspar, and plagioclase)
igneous
Granite
Felsic Intrusive Igneous Rock
igneous
Granite
Granite (phaneitic intrusive igneous rock)
igneous
Gneiss
Gneiss (High-grade regional metamorphic rock)
metamorphic
Granodiorite
Granodiorite (Intermediate intrusive igneous rock)
igneous
Diorite
Diorite (Intermediate intrusive igneous rock)
igneous
Granite Gneiss
Felsic Gneiss (composed of Quartz, Feldspar, and Biotite)
metamorphic
Granite
Intrusive Igneous Rock
igneous
Serpentinite (likely serpentinized ultramafic rock)
Serpentine-group minerals, chiefly antigorite/lizardite; commonly derived from peridotite
metamorphic
Blue-green raw mineral specimen, likely apatite
Fluorapatite, Ca₅(PO₄)₃F (probable; visual identification only)
mineral
Porphyritic polymictic breccia (likely volcanic breccia)
Volcanic breccia; probable polymictic andesite–dacite breccia with quartz/feldspar clasts
igneous
Serpentinized ultramafic rock with magnesite
Serpentinite, chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), with likely magnesite (MgCO₃) and minor chromite/magnetite
metamorphic
Eclogite
Eclogite (Omphacite-Garnet rock)
metamorphic
Quartzite
Quartzite (primarily SiO2)
metamorphic
Granite
Phaneritic Felsic Igneous Rock
igneous
Granite
Phaneritic Felsic Igneous Rock
igneous
Granite
Phaneritic Felsic Igneous Rock
igneous
Granite
Granite (Plutonic Igneous Rock)
igneous
Granite
Granite (composed primarily of Quartz, Alkali Feldspar, and Plagioclase)
igneous
Granite
Phaneritic plutonic rock (approx. 20-60% quartz, 35-90% feldspar)
igneous
Pink Granite
Potassium Feldspar-Rich Granite
igneous
Granite
Granite (Alkali-feldspar, Quartz, and Plagioclase composition)
igneous
Granite (Dioritic or Hornblende-rich)
Phaneritic Plutonic Felsic to Intermediate Igneous Rock
igneous
Weathered sandstone or siltstone
Clastic sedimentary rock, chiefly quartz and feldspar grains cemented by silica, iron oxides, or carbonate
sedimentary
Manganese Dendrite on Siltstone
Manganese Oxide (pyrolusite or psilomelane) Dendrites
mineral/sedimentary
Pyrite Sun (Pyrite Dollar)
Iron Disulfide (FeS2)
mineral
Gneiss
Gneiss
metamorphic
Quartzite
Metamorphosed Quartz Sandstone (SiO2)
metamorphic
Granite
Granite (Felsic Plutonic Rock)
igneous
Uncertain polymict breccia or altered volcanic rock
Likely hydrothermally altered volcanic breccia; exact mineral identification requires testing
igneous
Eclogite
Eclogite (Omphacite-Garnet rock)
metamorphic