Sedimentary (Processed Mineral Product)

Schist (Garnet-Mica Schist)

Garnet-Mica Schist (X-Y)3Z2(SiO4)3

Jasper Breccia

Silicon Dioxide (SiO2) with impurities

Quartz Geode (likely within Limestone or Dolomite matrix)

Quartz (SiO₂)

Sandstone

Sandstone (lithified arenite/wacke)

Petrified Wood

Silicified Wood (primarily SiO₂ - Silicon Dioxide)

Vanadinite

Lead Chlorovanadate, Pb5(VO4)3Cl

Red Jasper

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Chert with Desert Varnish

Cryptocrystalline Quartz (SiO2) with Manganese/Iron oxide coating

Green Aventurine

Quartzite with Fuchsite inclusions (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)

Leopard Skin Jasper

Silicon Dioxide (SiO2) with impurities

Laterite (iron-rich nodule, possibly Bauxite as a subtype)

Laterite (composed of various minerals including goethite, hematite, gibbsite, etc.)

Quartz Vein in Host Rock

Silicon Dioxide (SiO2)

Petrified Wood (Silicified Fossil)

Silicified Wood (SiO2)

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Red Coral (Precious Coral)

Corallium rubrum (Calcium Carbonate, CaCO3)

Petrified Wood

Silicified Wood (SiO2)

Blue Dyed Agate

Chalcedony (SiO2) with artificial pigment

Red Jasper (Siltstone variant)

Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions

Yellow Jasper

Silicon Dioxide (SiO2) with iron hydroxides

Red Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Chert (Flint variety)

Silicon Dioxide (SiO2)

Jasper (Iron-stained Quartzite/Chert)

Silicon Dioxide (SiO2) with iron oxide inclusions

Man-made Jewelry Charm (Enameled Metal)

Not a natural mineral; composed of base metal alloy (likely zinc or brass) and epoxy resin/enamel.

Biotite Schist (likely)

Biotite Schist (rock), Biotite (mineral)

Ferruginous Quartz on Ironstone

Silicon Dioxide (SiO2) with Hematite (Fe2O3)

Sandstone (Pebble/Conglomerate fragment)

Sandstone (clastic sedimentary rock)

Dyed Agate

Silicon Dioxide with artificial pigment (SiO2)

White Marble

Recrystallized Calcite (CaCO3)

Quartz (vein quartz)

SiO2 (Silicon Dioxide)

Porphyry (Flower Stone)

Porphyry (Andesite or Basalt matrix)

Ferruginous Quartz (Hematoid Quartz)

Silicon Dioxide (SiO2) with Hematite or Goethite inclusions

Red Jasper

Silicon Dioxide (SiO2) with Hematite impurities

Falcon's Eye (Blue Tiger's Eye)

Pseudomorph of Quartz after Crocidolite (SiO2)

Blue Goldstone

Aventurine Glass

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.

Sandstone

Sandstone (arenite is a more specific geological term for a clean sandstone, while wacke refers to a dirty sandstone with significant matrix)

Sea Glass (White/Clear)

Amorphous Silica (Alkali-Lime-Silica Glass), SiO2 + Na2O + CaO

Concretion or Geode (unbroken)

Varied (depending on mineral composition and cementing agent). For quartz-lined geodes, the scientific name of the dominant mineral would be Quartz (SiO2). For calcite-lined geodes, Calcite (CaCO3). Concretions are often composed of cryptocrystalline quartz (chert), calcite, or iron oxides.

Chert (Quartzite-rich River Pebble)

Silicon Dioxide (SiO2)

Ferruginous Conglomerate

Ferruginous Conglomerate (Clastic Sedimentary Rock)

River Stone (River Pebbles)

Alluvial Deposit (typically Quartzite, Sandstone, or Granite clasts)

Jasper (Petrified Wood Variety)

Silicon Dioxide (SiO2)