Igneous And Metamorphic Derivative (Weathered)

Milky quartz

Quartz (silicon dioxide, SiO₂), massive variety

Dark, coarse-grained rock fragment (possibly amphibolite or gabbro)

Uncertain from the photo; likely amphibolite (hornblende-rich metamorphic rock) or a mafic igneous rock such as gabbro

Quartz-veined Metamorphic Rock (Wishing Stone)

Quartz-veined Metamorphic/Igneous Host Rock with Quartz Veinlets

Milky quartz

Quartz (silicon dioxide, SiO₂)

Pyrite

Iron Sulfide (FeS2)

Yellow Quartz (Citrine Quartz / Milky Quartz)

Silicon Dioxide (SiO2)

Milky Quartz with Iron Inclusions

Silicon Dioxide (SiO2)

Weathered quartz-rich rock, possibly pegmatite or quartzite

Quartz (SiO₂)-rich aggregate; exact identification is uncertain from the photograph

Banded metamorphic rock, likely gneiss

Gneiss; predominantly quartz–feldspar with mica/amphibole minerals

Weathered gray metamorphic rock, likely schist or slate

Foliated silicate rock; possibly mica schist or phyllite

Unidentified greenish-gray rock fragment

Tentatively altered basalt or basaltic volcanic rock; mineral identification requires testing

Black Tourmaline (Schorl)

Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)

Banded gneiss pebble

Biotite–quartz–feldspar gneiss (composition variable)

General river rock or weathered cobble

Mixed rock composition

Likely quartz-rich pegmatite (weathered, mica-bearing)

Granitic pegmatite, composed mainly of quartz and feldspar with possible mica; exact minerals cannot be confirmed from the photo

Magnetite / Hematite (Iron Ore Pebble)

Fe3O4 (Magnetite) / Fe2O3 (Hematite)

Quartz pebble

Silicon dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Weathered limestone or calcareous tufa

Calcite-rich carbonate rock, primarily CaCO₃ (often micritic limestone or travertine/tufa)

Tumbled quartz crystal

Quartz (silicon dioxide, SiO₂)

Magnetite-rich iron ore

Magnetite (Fe₃O₄), possibly mixed with hematite or metallic sulfides

Milky quartz pebble

Quartz (silicon dioxide, SiO₂)

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

Quartz (SiO₂), potentially with iron-oxide inclusions

Mixed rock and mineral collection

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

Sandstone (Micaceous Sandstone)

Arenite (SiO2 with KAl2(AlSi3O10)(OH)2 inclusions)

Quartz (Water-worn pebble)

Silicon Dioxide (SiO2)

Sapphire (Corundum)

Corundum (Al2O3)

Quartz Pebble (Milky Quartz)

Silicon Dioxide (SiO2)

Weathered quartz-rich pebble

Milky quartz, likely with iron-oxide staining; exact rock type uncertain from image

Weathered gneissic metamorphic rock

Gneiss, likely quartz–feldspar–mica gneiss

Dark weathered igneous rock, likely basalt

Basalt; chiefly plagioclase feldspar, pyroxene, and commonly olivine or iron oxides

Quartz with Host Rock Matrix

Silicon Dioxide (SiO2)

Weathered greenish-gray rock fragment

Tentatively basaltic or mafic metamorphic rock; exact identification is uncertain from the photograph

Quartz-rich rock, possibly milky quartz or quartzite

Quartz (silicon dioxide, SiO₂); exact specimen identification is uncertain from the image

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Weathered quartz-rich rock, likely quartzite

Quartzite, composed mainly of quartz (SiO₂); identification is tentative from the image

Hematite

Hematite (Α-Fe2O3)

Weathered granite or granitic gneiss

Granite; chiefly quartz, feldspar, and mica, possibly with gneissic foliation

Quartz-rich feldspathic pebble, possibly granite or granitic gneiss

Quartz–feldspar aggregate, likely granite; dark inclusion may be biotite, hornblende, or iron-oxide staining

Feldspar

Potassium Feldspar (KAlSi3O8)

Milky quartz (likely weathered quartzite or quartz vein fragment)

Quartz, silicon dioxide (SiO₂)

Quartz (likely a form of massive or vein quartz)

Quartz (SiO₂)