Sedimentary Rock (Possibly Composed Of Various Minerals)

Bauxite

Bauxite (Al2O3·2H2O mixed with iron oxides)

Quartz-rich metamorphic rock, likely milky quartz or quartzite

Quartz (SiO₂); possibly quartzite composed predominantly of recrystallized quartz

Sandstone

Sandstone (lithified sand)

Tumbled Mixed Gemstones and Rocks

Various mineral species including quartz (SiO2) and silicate minerals

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 (Tumbled)

Silicon Dioxide (SiO2)

Slate

Slate (foliated metamorphic rock)

Quartz Boulder

Silicon Dioxide (SiO2)

Sandstone

Quartz Sandstone (predominantly)

Red Sandstone

Arenite (Iron-rich)

White Quartz

Silicon Dioxide (SiO2)

Red-and-green jasper

Jasper, microcrystalline quartz (SiO₂), colored mainly by iron oxides and possibly chlorite/epidote

Sandstone

Sedimentary rock composed mainly of quartz sand

Sandstone

Clastic sedimentary rock

Given the appearance, it's likely a fragment of an igneous or metamorphic rock composed of multiple minerals. Without specific diagnostic features, it's difficult to give a common name other than 'crystalline rock fragment'. If pressed to guess based on the granular, somewhat light and dark speckled appearance, it could be a fragment of granite or a related intrusive igneous rock.

As a rock fragment, it does not have a single scientific mineral name; rather, it's a piece of a rock which is a combination of minerals. If it were granite, its main mineral composition would be quartz (SiO2), feldspar (e.g., KAlSi3O8 - orthoclase, (Na,Ca)(Al,Si)4O8 - plagioclase), and mica (e.g., KAl2(AlSi3O10)(OH)2 - muscovite or K(Mg,Fe)3AlSi3O10(OH)2 - biotite), among others.

Milky Quartz in Shale

Silicon Dioxide (SiO2) in sedimentary host rock

Dark rounded pebble, possibly basalt

Basalt (fine-grained mafic volcanic rock; identification tentative from photograph)

Dalmatian Stone

Dalmatian Jasper (a trade name for an igneous microcrystalline rock composed mostly of feldspar, quartz, and dravite)

Dendritic Chalcedony (Agate)

Cryptocrystalline Quartz (SiO2)

Gray-green rough stone, possibly serpentinite

Indeterminate from the photograph; possible serpentinite, a rock composed mainly of serpentine-group minerals

Marble

Metamorphosed Limestone

Sandstone (Quartz-rich)

Arenite (composed primarily of SiO2)

Sandstone (Ferruginous)

Clastic Sedimentary Rock (Sandstone)

Shale

Fissile mudrock (composed primarily of clay minerals and quartz)

Quartz (Float/Abraded)

Quartz (SiO₂)

Fossil-bearing concretion, possibly containing a fossil shell or other organic inclusion

Calcareous concretion; exact fossil and host-rock composition are not identifiable from the image

Fossil Snail Shell (Embedded in Resin)

Gastropoda fossil

Sandstone

Arenite (composed primarily of SiO2)

Bauxite

Bauxite (Mixture including Gibbsite Al(OH)3, Boehmite γ-AlO(OH), and Diaspore α-AlO(OH))

Garnet in Schist (Garnetiferous Micaceous Schist)

Almandine Garnet, Fe3Al2(SiO4)3

Kambaba Jasper (Crocodile Jasper)

Stromatolitic Rhyolite/Jasper (SiO2)

Clay (as a rock-forming material)

Clay minerals (e.g., Kaolinite group, Smectite group, Illite group, Chlorite group)

Unidentifiable Rock Fragment

Beaded Jewelry (Assorted Gemstones)

Various minerals, including but not limited to Quartz (SiO2), Garnet (X3Y2(SiO4)3), Jade (Na(Al,Fe)Si2O6), Amethyst (SiO2),等の多様な組み合わせ

Peridotite

Ultramafic intrusive igneous rock

Dyed Dalmatian Stone

Aplite (Alkali-feldspar granite) with Arfvedsonite

Dalmation Jasper (or Dalmation Stone)

Dalmation Stone (composed of Perthite, Quartz, and Arfvedsonite)

Sandstone (Red)

Arenite (composed primarily of SiO2)

Magnetite

Iron(II,III) oxide (Fe3O4)

Sandstone (with minor weathering/pitting)

Clastic Sedimentary Rock (composed mostly of SiO2)

Chert (Jasper or Flint variant)

Chert (composed of microcrystalline quartz, SiO2)

Limonite with Hematite

Hydrated iron(III) oxide-hydroxide with variable composition (FeO(OH)·nH2O)