The Purple Specimen Is A Mineral (Amethyst); The White Specimen Is A Sedimentary Rock (Limestone Or Marble).

Carnelian and White Quartz Bracelet

Silicon Dioxide (SiO2) - specifically Carnelian (Chalcedony) and Rock Crystal/Snow Quartz

Sandstone (Ferruginous)

Arenite (composed primarily of SiO2 with Fe2O3 cement)

Chert (and Limestone)

Silicon Dioxide (SiO2)

Sandstone (Flagstone)

Arenite (composed primarily of SiO2)

Fossiliferous Limestone

Limestone with fossil inclusions (CaCO3)

Sandstone

Arenite (Siliclastic sedimentary rock)

Druzy Quartz

Silicon Dioxide (SiO2)

Quartz (Iron-Stained or Milky Quartz)

Silicon Dioxide (SiO2)

Banded Agate

Chalcedony / Silicon Dioxide (SiO2)

Gneiss

High-grade metamorphic rock (Gneiss)

Chert Pebble (Yellow/Brown Jasper variety)

Microcrystalline Quartz (SiO2)

Chert (Jasper/Flint Pebble)

Microcrystalline or Cryptocrystalline Silicon Dioxide (SiO2)

Banded Agate (specifically Lake Superior Agate)

Silicon dioxide (SiO2) - Cryptocrystalline Chalcedony

Quartz (Milky/Iron-stained)

Silicon Dioxide (SiO2)

Yellow Quartz (Citrine-colored Quartz)

Silicon Dioxide (SiO2)

Red Jasper with Quartz and Hematite

Silicon Dioxide (SiO2) with Ferric Iron inclusions

Quartz Pebble

Silicon Dioxide (SiO2)

Rough Agate/Chert Nodules

Cryptocrystalline Quartz (SiO2)

Quartz Crystal

Silicon Dioxide (SiO2)

Granite

Phaneritic Felsic Igneous Rock

Lepidolite with Quartz

K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2

Quartz Geode

Silicon Dioxide (SiO2)

Pink Granite

Phaneritic Plutonic Igneous Rock (high K-feldspar)

Biotite (Black Mica)

Biotite - K(Mg,Fe)3AlSi3O10(F,OH)2

Massive Quartz (Yellow/Citrine variety)

Silicon Dioxide (SiO2)

Moss Agate

Silicon Dioxide (SiO2) with inclusions of Manganese or Iron oxide

Sedimentary Breccia

Breccia (Clastic Sedimentary Rock)

Sandstone Cobble with Liesegang Rings

Arenite with iron oxide precipitation (SiO2 matrix with Fe2O3 banding)

Agate

Chalcedony (Silicon Dioxide, SiO2)

Basalt Pebble

Basalt

Pyrite in Shale

Iron Sulfide (FeS2) in Sedimentary Matrix

Amethyst

Amethyst (variety of Quartz, SiO2)

Amethyst

Silicon Dioxide (SiO2)

Citrine

Silicon Dioxide (SiO2) with iron impurities

Sandstone (specifically Flagstone)

Arenite (primarily composed of SiO2)

Chert (with Quartz Vein)

Chert (Siliceous sedimentary rock, predominantly Microcrystalline Quartz SiO2)

Amethyst

Quartz (Silicon Dioxide) with Ferric Iron impurities - SiO2

Dalmatian Stone (often called Dalmatian Jasper)

Peralkaline Feldsphathic Igneous Rock

Basalt (River Stone)

Basalt

Garnet Schist

Garnet-bearing Mica Schist (variety of compositions, often Al2SiO5 with X3Y2(SiO4)3)

Quartzite Beach Pebble

Quartzite (primarily SiO2)

Chert (specifically Iron-stained or Jasperoid Chert)

Microcrystalline Quartz (SiO2)