Unknown (Likely Sedimentary Or Metamorphic)

Small quartz-rich stone, possibly iron-stained quartz or jasper

Quartz (SiO₂), potentially with iron-oxide inclusions

Pyrite-bearing quartz specimen

Pyrite (FeS₂) with quartz (SiO₂), possibly minor mica or chalcopyrite

Mixed rock and mineral collection

Multiple specimens; visible pieces may include quartz, calcite, agate/chalcedony, jasper, and dyed or coated materials

Pyrite in Matrix (Quartz/Schist)

Iron Sulfide (FeS2)

Polished blue-gray stone, likely labradorite or gneiss

Labradorite-bearing gneiss; plagioclase feldspar-rich rock

Weathered quartz-rich sandstone or quartzite

Quartzite (predominantly SiO₂), possibly strongly cemented sandstone

Pyrite-bearing rock (likely pyrite-rich schist or massive pyrite)

Pyrite, FeS₂, possibly in a micaceous metamorphic matrix

Tumbled orange-brown quartz pebble

Likely iron-stained quartz or chalcedony (SiO₂)

Weathered sandstone or iron-rich sedimentary fragment

Quartz-rich sandstone, possibly ferruginous sandstone (SiO₂-dominant)

Tumbled beach pebble (likely quartz-rich sandstone or chert)

Indeterminate lithic clast; likely quartz (SiO₂)-rich sandstone/chert

Iron-stained metamorphic rock, likely quartzite or jasper

Quartz-rich rock dominated by SiO₂, with iron oxides/hydroxides (hematite, goethite) and possible clay or mica

Polished/tumbled iron-rich jasper (likely brecciated jasper)

Jasper, microcrystalline quartz (SiO₂) colored chiefly by iron oxides/hydroxides

Gneiss

Gneiss (High-grade metamorphic rock)

Honey calcite (likely calcitic limestone or marble)

Calcite — CaCO₃; possibly calcite-rich limestone/marble

Likely slate or fine-grained metamorphic stone with quartz vein

Slate–phyllite, composed mainly of quartz, mica, and chlorite; the white vein is likely quartz

Quartz–mica metamorphic rock, likely schist

Quartz–muscovite/biotite schist; predominantly SiO₂ quartz with phyllosilicate micas

Jasper

Jasper (Silicon Dioxide, SiO2)

River Cobbles (Quartzite and Sandstone)

Metamorphosed Quartz-rich Sedimentary Rock

Mica-rich metamorphic rock, likely phyllite or schist

Quartz–mica schist/phyllite; chiefly muscovite or biotite mica with quartz and feldspar

Mica-rich metamorphic rock, likely biotite schist or phyllite

Quartz–feldspar–mica schist/phyllite; commonly containing biotite, muscovite, and minor sulfides

Pearl-bearing oyster shell

Nacreous shell, primarily aragonite (CaCO₃), with natural pearls (calcium-carbonate nacre)

Conglomeratic concrete or asphalt aggregate surface with dark bituminous chunks

Polymictic gravel aggregate; dark pieces likely bitumen/asphalt, not a natural rock

Tiger iron slab (likely polished banded iron formation)

Banded iron formation (BIF), chiefly hematite/magnetite, quartz, and iron-rich amphibole or jasper

Gneiss (Metamorphosed Pebble)

Gneiss with Quartz/Feldspar banding

Tumbled quartzite pebble

Quartzite, predominantly crystalline SiO₂

Biotite schist

Mica schist; chiefly quartz, feldspar, and biotite mica

Tumbled quartz pebble (likely milky quartz or chalcedony)

Quartz, SiO₂; possibly microcrystalline quartz (chalcedony)

Blue apatite (likely rough/tumbled specimen)

Apatite group, commonly fluorapatite — Ca5(PO4)3F

Yellow-orange quartz/chalcedony pebble (possibly citrine-bearing)

Quartz, SiO₂; likely microcrystalline chalcedony with iron staining

Gneiss (with Quartz and Mica)

Gneiss

Polished banded metamorphic stone, likely gneiss or quartzite

Banded quartz–feldspar–mica rock; precise identification requires testing

Pyrite-bearing schist (likely mica schist)

Muscovite–quartz schist with disseminated pyrite (FeS₂)

Iron-stained quartzite or quartz-rich metamorphic rock

Quartzite, predominantly SiO₂, with iron-oxide coatings (goethite/hematite)

Tourmaline-rich schist (likely black tourmaline)

Schist containing schorl, Fe-rich NaFe3Al6(BO3)3Si6O18(OH)4

Mixed pebble collection, including likely flint, quartzite, and fossil material

Varied silicate rocks; visible specimen may include chert (microcrystalline SiO₂), quartzite, and a possible fossil

Weathered quartz-bearing rock, possibly sandstone or quartzite

Provisional: quartzite (mostly SiO₂); could alternatively be iron-stained quartz sandstone

Banded Gneiss

Gneiss (High-grade regional metamorphic rock)

Quartz-rich rock, likely quartzite or weathered sandstone

Quartzite (mostly SiO₂); possibly quartz arenite sandstone

Foliated metamorphic rock, likely gneiss or schist

Biotite–quartz–feldspar gneiss/schist; exact identification requires a fresh surface and testing

Polished dark gemstone, likely hematite or magnetite

Hematite (Fe₂O₃) or magnetite (Fe₃O₄); exact identification requires testing

Tumbled quartz (likely milky or rose quartz)

Quartz, silicon dioxide (SiO₂)

Weathered quartz-rich rock, likely quartzite

Quartzite (mostly SiO₂), possibly quartz-rich sandstone or milky quartz vein material