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

Blue Chalcedony

Microcrystalline Quartz (SiO2)

Quartz

Silicon Dioxide (SiO2)

Dendritic Agate (River Pebble)

Silicon Dioxide (SiO2) with Manganese or Iron oxide inclusions

Breccia

Breccia

Granite Pebble (Salt and Pepper Granite)

Felsic Intrusive Igneous Rock (Granite)

Clear Quartz

Silicon Dioxide (SiO2)

Agate (specifically Carnelian or Honey Agate)

Silicon Dioxide (SiO2)

Jasper with Quartz Vein

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Painted Garden Rock (likely Granite or Limestone base)

Silicon Dioxide (SiO2) / Calcium Carbonate (CaCO3) based substrate with Acrylic/Enamel pigments

US Penny

Cuprum (Copper: Cu) and Zincum (Zinc: Zn) Alloy

Druzy Quartz Geode (likely Smokey Quartz variety)

Silicon Dioxide (SiO2) - specifically a geode formation lined with druzy quartz crystals, with a likely brownish hue indicating smokey quartz.

Pyrite (on Quartz matrix)

Iron Disulfide (FeS2)

Pyrite (Fools Gold)

Iron Sulfide (FeS2)

Milky Quartz

Silicon Dioxide (SiO2)

Hematite

Iron(III) oxide (Fe2O3)

Clear Quartz Crystal

Quartz (Silicon Dioxide, SiO2)

Pyrite (Iron Pyrite)

Iron Sulfide (FeS2)

Quartz (Druzy/Crystalline)

Silicon Dioxide (SiO2)

Cobaltian Calcite (Cobaltoan Calcite)

Cobalt-bearing Calcite (Ca,Co)CO3

Pearl

Calcium Carbonate (CaCO3) with Conchiolin

Blue Apatite

Fluorapatite / Chlorapatite [Ca5(PO4)3(F,Cl,OH)]

Agate (specifically, likely a geode slice or nodule)

Agate (a variety of Chalcedony, with chemical formula SiO2)

Fluorite

Calcium Fluoride (CaF2)

Quartz Vein in Host Rock

Silicon Dioxide (SiO2) in matrix

Granite

Granite (a common term for a felsic intrusive igneous rock)

Quartz

Quartz (SiO2)

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Pegmatite (likely Granitic Pegmatite)

Pegmatite (a coarse-grained igneous rock, often with granitic composition)

Quartz (Milky or Smoky variant)

Silicon Dioxide (SiO2)

Gold Nugget

Native Gold (Au)

Diamond

Cubic carbon (C)

Yellow Quartz (Citrine or Iron-Stained Quartz)

Silicon Dioxide (SiO2)

Blue Chalcedony (Tumbled)

Silicon Dioxide (SiO2)

Pyrite

Iron Disulfide (FeS2)

Rough Sapphire

Corundum (Al2O3)

Sandstone (likely Arkose or Quartz Sandstone)

Clastic sedimentary rock (primarily SiO2)

Jade

Jade can refer to two distinct minerals: Nephrite (a variety of the mineral actinolite, Ca2(Mg,Fe)5Si8O22(OH)2) and Jadeite (Na(Al,Fe3+)Si2O6). Based on the image, showing a relatively uniform green color and possibly slight translucence in bead form, it is very likely one of these, but determining which one from a photo is difficult without specific testing.

Black Tourmaline

Schorl (Sodium Iron Aluminum Borosilicate Hydroxide), NaFe3Al6(BO3)3Si6O18(OH)4

Bog Iron / Limonite Concretion

Goethite/Limonite mixture (FeO(OH)·nH2O)

Quartz Crystal with Inclusions

Silicon Dioxide (SiO2)

Gold

Native Gold (Au)

Chert (Flint)

Chert (predominantly SiO₂ - silicon dioxide)