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

Lapis Lazuli

Complex mixture of minerals, primarily Lazurite (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2

Chert (Brecciated River Cobble)

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Sandstone (with Iron concretions/staining)

Arenite (composed primarily of Quartz and Feldspar with Iron Oxide cement)

Amber Flint (Chert)

Cryptocrystalline Quartz (Silicon Dioxide, SiO2)

Sandstone (likely Greywacke or Lithic Sandstone)

Arenite / Wacke

Ironstone Concretion (Boji Stone/Moqui Marble type)

Goethite/Hematite-encrusted Sandstone Concretion

Chert (specifically Yellow Jasper)

Sedimentary Cryptocrystalline Quartz (SiO2)

Mexican Crazy Lace Agate

Silicon Dioxide (SiO2) with iron and aluminum inclusions

Lavender Quartz (appearing as beads) and Druzy Quartz

Silicon Dioxide (SiO2)

Amethyst

SiO2 (Silicon Dioxide with iron impurities)

Fossiliferous Limestone (Chertified Limestone)

Calcium Carbonate (CaCO3) often replaced by Microcrystalline Silica (SiO2)

Crushed Limestone Aggregate

Limestone (Calcium Carbonate, CaCO3)

Sandstone with Concretions / Liesegang Rings

Arenite with iron oxide banding

Corundum (Sapphire/Ruby in Matrix)

Aluminium oxide (Al2O3)

Crushed Limestone and Calcite

Calcium Carbonate (CaCO3)

Tree Agate

Silicon Dioxide (SiO2) - Dendritic Agate/Chalcedony

Amethyst

Silicon Dioxide (SiO2) with Iron impurities

Fossil Coral

Coral Limestone (a type of biogenic sedimentary rock)

Quartz (with iron oxide staining)

Silicon Dioxide (SiO2)

Quartz

Quartz (SiO₂ - Silicon Dioxide)

Citrine (Quartz variant)

SiO2 (Silicon Dioxide)

Sandstone (Weathered Cobble)

Clastic sedimentary rock (primarily SiO2)

Fossiliferous Limestone with Brachiopod Mold

Calcium Carbonate (CaCO3) matrix containing Brachiopoda fossil impressions

Amethyst

Quartz (Silicon Dioxide) with Iron impurities, SiO2

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Quartz

Quartz (SiO₂ - Silicon Dioxide)

Lapis Lazuli

Lazurite-rich metamorphic rock (approx. Na6Ca2(Al6Si6O24)(S,SO4,Cl)1,2)

Sandstone (likely Quartzose Sandstone)

Arenite (SiO2 based)

Dalmatian Stone (commonly Dyed)

Dalmatian Jasper (Peralkaline igneous rock)

Quartzite (River Pebble)

Metamorphosed Quartz Sandstone (primarily SiO2)

Fossilized Coral (Petoskey Stone / Favosites)

Favosites (extinct genus of tabulate coral)

Raw Citrine

Citrine (Silicon Dioxide, SiO2)

Amethyst (Tumbled Chips)

Amethyst (Silicon Dioxide with Iron impurities, SiO2)

Chert (specifically Jasper/Brown Chert)

Silicon Dioxide (SiO2)

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Chert (Jasper/Mudstone)

Silicon Dioxide (SiO2)

Banded Agate Geode

Silicon Dioxide (SiO2)

Sandstone (with potential fossil inclusions)

Clastic sedimentary rock (primarily SiO2)

Amethyst (Geode)

Silicon Dioxide with Iron impurities (SiO2)

Lapis Lazuli (in Matrix)

Na8[Al6Si6O24]S2 (Lazurite as the primary component)

Chert (varietal: Jasper or Flint likely, but definitive identification is difficult from image)

SiO₂ (silicon dioxide)