Mineral Based Composite

River Pebble

Quartzite / Weathered Sedimentary Rock

Turquoise cabochon (likely stabilized or imitation)

Turquoise, hydrated copper aluminum phosphate: CuAl₆(PO₄)₄(OH)₈·4H₂O

Unakite

Unakite Epidosite (composite of Epidote, Orthoclase, and Quartz)

Opalite crescent pendant

Opalite (man-made opalescent glass; not a natural mineral)

Moon (lunar surface depiction)

Lunar rock; chiefly anorthosite, basalt, and breccia (plagioclase-rich CaAl2Si2O8)

Sandstone

Arenite

Sandstone (Quartz Sandstone / Iron-stained Sandstone)

Sandstone (SiO2 with iron oxide impurities)

Banded Onyx (Mexican Onyx / Travertine)

Calcite (CaCO3) - Banded Travertine

Tumbled turquoise cabochon

Turquoise, CuAl₆(PO₄)₄(OH)₈·4H₂O; possibly stabilized or dyed material

Sandstone (with potential trace fossils)

Clastic sedimentary rock (primarily SiO2)

Blue-green cabochon pendant, likely turquoise or composite turquoise

Turquoise: hydrated copper aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O; exact identification is uncertain from the blurred image

Gold Mineral

Native Gold (Au)

Blue-green chrysocolla rough specimen

Chrysocolla, hydrated copper aluminosilicate; commonly associated with malachite, quartz, and limonite

Dendritic sandstone

Sandstone with Manganese Oxide dendrites

Fossilized turtle shell or carapace

Testudines indeterminate; shell mainly fossilized calcium-carbonate bone (apatite)

Green Moss Agate

Agate (Silicon Dioxide, SiO2) with inclusions

Engineerged Quartz (Quartz Composite)

SiO2 (Silicon Dioxide) in a polymer resin matrix

Tree Agate

Silicon Dioxide (SiO2) with Dendritic Inclusions

Granite

Granite (Phaneritic Igneous Rock)

Quartzite (Aventurine type)

Metamorphosed Quartz Sandstone (SiO2 with inclusions)

Fossilized coral with attached shell

Likely fossil coral (Scleractinia or Tabulata), with a bivalve or gastropod shell; exact identification requires microscopy

Polished chrysocolla cabochon

Chrysocolla, a hydrated copper phyllosilicate; commonly intergrown with quartz, malachite, or other copper minerals

Polished blue spotted stone, likely K2 stone

K2 stone: granite containing blue azurite spots; quartz–feldspar–biotite matrix

Red Moss Agate (Jasper)

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Opalite glass sphere (likely synthetic imitation)

Man-made opalescent glass; not natural opal

Rose Quartz

Silicon dioxide (SiO2) with traces of titanium, iron, or manganese

Sandstone Pebble

Arenite (SiO2 with minor mineral cements)

Dendritic Agate

Silicon Dioxide (SiO2) with Manganese/Iron oxide inclusions

Muscovite Mica

Muscovite KAl2(AlSi3O10)(OH)2

Sandstone

Arenite (primarily Quartz-based)

Sandstone

Arenite (SiO2 based typically)

Sandstone

Arenite (SiO2 based typically)

Gold

Native gold (Au)

Bumblebee Jasper

Anhydrous Calcium Carbonate with Sulfur and Arsenic (Orpiment/Realgar)

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.

Tumbled orbicular jasper

Orbicular jasper; microcrystalline quartz (SiO₂) with iron oxides and feldspathic/chalcedony inclusions

Calcite crystal cluster

Calcite (calcium carbonate, CaCO₃)

Sandstone

Arenite (SiO2 based with various mineral cements)

Sandstone (likely Calcareous or Quartz-rich)

Arenite (SiO2 based typically)

Sandstone (Ferruginous)

Arenite (SiO2 based with Fe2O3 banding)

Sandstone

Arenite (SiO2 based with various mineral cements)

Purple Turquoise (Composite Mojave Turquoise)

CuAl6(PO4)4(OH)8·4H2O (Hydrated copper aluminum phosphate composite)