This Appears To Be A Man Made Metallic Object, Likely Jewelry, Not A Natural Rock, Mineral, Or Geological Specimen.

Banded Gneiss (Variety of Gneiss)

Gneiss (specifically, a variety exhibiting prominent banding; mineral composition can vary, but often contains quartz, feldspar, mica, and amphibole)

Chert (Jasper variation)

Silicon dioxide (SiO2)

Lapis Lazuli (polished cabochon)

Lazurite-rich metamorphic rock (approx. Na6Ca2Al6Si6O24(SO4,S,Cl)2)

Quartz (Milky Quartz)

Quartz (SiO2 - Silicon Dioxide)

Turquoise

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

White Quartz

Silicon Dioxide (SiO2)

Pink Sapphire

Corundum (Al2O3) with Chromium/Iron/Titanium trace impurities

Schist

Mica Schist (Group of medium-grade metamorphic rocks)

Ironstone Concretion (Moqui Marble variety)

Ferruginous Sandstone Concretion

Red Jasper (beads)

Silicon Dioxide (SiO2) with iron inclusions

Agate (or Chalcedony)

SiO2 (Silicon Dioxide) - a cryptocrystalline variety of quartz

Petrified Wood

Silicified Wood (SiO2)

Quartz (Druzy/Macro-crystalline)

Silicon Dioxide (SiO2)

Clear Quartz

Quartz (Silicon Dioxide, SiO2)

Aluminum Slag

Anthropogenic Aluminum (Al)

Hypersthene

(Mg,Fe)SiO3 - Enstatite-Ferrosilite series

Ruby (set in a gold pendant)

Ruby (Variety of Corundum, Al2O3)

Marble

Metamorphosed Limestone/Dolomite

Quartz (Milky/Common)

Silicon Dioxide (SiO2)

Clear Quartz Crystal

Quartz (Silicon Dioxide - SiO2)

Botryoidal Chalcedony (Desert Rose / Agate)

Silicon Dioxide (SiO₂)

Quartz (Clear Quartz/Rock Crystal)

Silicon Dioxide (SiO2)

Rose Quartz

Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese

Obsidian

Amorphous volcanic glass (primarily SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Diamond

Diamond (C)

White Quartz

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silica / Silicon Dioxide), SiO2

Fossilized Coral (Petoskey-like or Favosites)

Anthozoa (Fossilized Coral)

River Rock / Stream Pebble

Fluvial Clast / Rounded Sedimentary Particle

Petrified Wood

Silicified Wood (primarily SiO2)

Mixed collection of Quartz varieties, Chalcedony, and metamorphic pebbles

Mixed gemstones (primarily Silicon Dioxide - SiO2)

Dalmation Stone (often called Dalmatian Jasper)

Peralkaline Rock (Microgranite/Aplite), SiO2 with inclusions of Arfvedsonite

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Limonite (Bog Iron)

Limonite (Hydrated iron(III) oxide-hydroxide) - FeO(OH)·nH2O

Sandstone Concretion

Moqui Marble / Ironstone Concretion (Iron oxide-cemented sandstone)

Clear Quartz

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Petrified Wood

Silicified Wood (SiO2)