Mineral Specimen

Wollastonite

Calcium Inosilicate, CaSiO3

Quartzite

Quartzite (SiO2)

Black Tourmaline

Schorl (NaFe2+3Al6(Si6O18)(BO3)3(OH,F)4)

Small dark mineral/rock fragment

Indeterminate; possibly magnetite-bearing basalt or iron-rich slag

Likely quartz-bearing metamorphic pebble

Indeterminate; probable quartzite or quartz-rich gneiss with dark mica/amphibole

Dumortierite Quartz

Dumortierite-bearing Quartz (SiO2 with Al7BO3(SiO4)3O3)

Milky Quartz

Quartz (Silicon Dioxide - SiO2)

Blue Apatite

Apatite Group (Ca5(PO4)3(F,Cl,OH))

Likely quartz crystal with iron-oxide staining

Quartz (SiO₂), possibly included or coated with limonite/goethite

Marble

Recrystallized Calcite (CaCO3)

Blue Apatite

Fluorapatite (Ca5(PO4)3F)

Black-and-white bicolored pebble

Likely basalt with a pale felsic or carbonate coating/inclusion; exact identification requires testing

Rounded greenish pebble

Indeterminate; possibly altered basalt, greenstone, or fine-grained serpentinite

Tumbled gray-blue stone, likely quartz-rich feldspar or granite pebble

Probable granitic fragment: quartz (SiO₂) with feldspar and minor mica; exact identification requires testing

Quartz-bearing granite or pegmatite fragment

Likely granitic material composed mainly of quartz (SiO₂), feldspar, and possibly biotite or hornblende

Small quartz-rich rock fragment (tentative)

Quartz, silicon dioxide (SiO₂), possibly in a feldspar-bearing granite fragment

Quartzite

Quartzite (primarily SiO2)

Pyrite

Iron Sulfide (FeS2)

Milky quartz

Quartz (silicon dioxide, SiO₂)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Limonite after Marcasite (Propeller Conchoid)

Goethite/Limonite pseudomorph after Marcasite (FeO(OH)·nH2O)

Quartz

Silicon Dioxide (SiO2)

Limonite Pseudomorph after Pyrite

Limonite (FeO(OH)·nH2O) replacing Pyrite (FeS2)

Pink potassium feldspar (orthoclase/microcline)

KAlSi₃O₈; likely massive potassium feldspar, possibly with quartz

Iron-rich reddish rock, possibly weathered basalt or ironstone

Indeterminate; likely oxidized mafic rock containing iron oxides and silicate minerals

Rounded iron-rich pebble, likely lateritic sandstone or ferruginous conglomerate fragment

Hematite/goethite-bearing ferruginous sediment; exact identification requires testing

Likely weathered iron-rich rock fragment

Indeterminate; possibly limonite/goethite-bearing sandstone or ironstone

Banded Iron Formation

Banded Iron Formation (BIF)

Olivine in Basalt matrix

Olivine (Magnesium Iron Silicate - (Mg, Fe)2SiO4)

Chalk

Calcium Carbonate (CaCO3)

Chrysocolla

(Cu,Al)2H2Si2O5(OH)4·nH2O

Ferrosilicon Slag (Industrial Vitrified Glass)

Vitreous Silicate Residue

Milky Quartz / Chalcedony

Silicon Dioxide (SiO2)

Rhodochrosite

Manganese Carbonate (MnCO3)

Weathered quartz-rich rock, possibly milky quartz or quartzite

Quartz (SiO₂), possibly quartzite with iron-oxide and dark-mineral inclusions

Small reddish-brown mineral fragment

Uncertain; possibly iron-stained quartz, feldspar, or garnet

Iron-stained quartz-rich rock, possibly goethite-bearing quartz

Quartz (SiO₂) with iron oxides/hydroxides, likely goethite or limonite

Rhodochrosite

Rhodochrosite (MnCO3)

Quartz-rich rock fragment, possibly granite or quartzite

Indeterminate quartz-bearing silicate rock; likely quartz (SiO₂) with feldspar and/or mica

Calcite

Calcium Carbonate (CaCO3)

Greenschist

Greenschist (Chlorite-Albite-Epidote Schist)

Howlite

Howlite (Ca2B5SiO9(OH)5)