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

Amethyst and Limestone

Amethyst (SiO2 - Silicon Dioxide) and Limestone (CaCO3 - Calcium Carbonate)

Amethyst Geode

Silicon Dioxide (SiO2) with iron impurities

Calcite on Matrix

Calcium Carbonate (CaCO3)

Marble

Recrystallized Calcite (CaCO3) or Dolomite (CaMg(CO3)2)

Marble

Recrystallized Carbonate Rock (CaCO3)

Amethyst and Agate Geode Section

Silicon Dioxide (SiO2) - Crystalline Quartz and Chalcedony

Marble (Carrara style)

Recrystallized Calcite-rich Metamorphic Rock (CaCO3)

Marble

Metamorphosed Limestone (calcite formulation CaCO3)

Marble

Recrystallized Calcite Rock (CaCO3)

White Marble

Recrystallized Calcite (CaCO3)

Druzy Quartz Geode (with Chalcedony)

Silicon Dioxide (SiO2)

Likely weathered limestone or calcitic marble

Calcite (CaCO₃), probably micritic limestone; marble is a possible metamorphic alternative

Quartz Geode (partially formed)

Silicon Dioxide (SiO2)

Amethyst Geode

Silicon Dioxide with trace inclusions of Iron (SiO2)

Quartz on Matrix

Silicon Dioxide (SiO2)

Amethyst (Chevron Amethyst)

Silicon Dioxide (SiO2) with iron impurities

Mixed rock and mineral specimen collection

Multiple species, likely quartz (SiO₂), calcite (CaCO₃), feldspar, chert, and assorted volcanic/sedimentary rocks

Amethyst

Amethyst (Silicon Dioxide - SiO2 with iron impurities)

Calcite

Calcium Carbonate (CaCO3)

Likely calcite-rich limestone

Calcite (CaCO₃), probably micritic or fossiliferous limestone

Likely limestone or marble fragment

Calcite-rich carbonate rock (CaCO₃); precise identification is uncertain from the image

Quartz Geodes and Crystal Clusters

Silicon Dioxide (SiO2)

Chevron Amethyst

Silicon Dioxide with Iron Impurities (SiO2)

Optical Calcite

Calcium Carbonate (CaCO3)

Geode with Quartz and Chalcedony

Silicon Dioxide (SiO2)

Mixed mineral and rock collection, including likely amethyst and assorted tumbled stones

Unidentified mixed specimens; visible purple quartz is likely amethyst (SiO₂)

White limestone

Calcite-dominated carbonate rock (CaCO₃), possibly chalky limestone

Clear Calcite

Calcite (Calcium Carbonate, CaCO3)

Chevron Amethyst

Silicon Dioxide (SiO2) with iron impurities

Amethyst Geode Fragment

Amethyst (Silicon Dioxide, SiO2) with Quartz matrix

White marble

Calcite marble (predominantly CaCO₃)

Amethyst-bearing quartz cluster

Quartz, SiO₂; purple variety: amethyst

Dyed Quartz Geode

Silicon Dioxide (SiO2) with artificial purple dye

Orange Calcite

Calcium Carbonate (CaCO3)

Light-colored limestone or marble fragment

Calcite-rich carbonate rock; likely limestone (CaCO₃), possibly recrystallized marble

Likely limestone or marble fragment

Calcite-rich carbonate rock; possibly marble (CaCO₃)

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Amethyst geode/druse

Quartz, SiO₂; purple variety amethyst

Geode (unopened) or Calcareous Nodule

Siliceous or Calcareous Concretion/Nodule

Geode (Unopened)

Silicon Dioxide (SiO2) in sedimentary vugs

Yellow Calcite

Calcite (Calcium Carbonate, CaCO3)

Banded limestone or marble

Calcite-rich carbonate rock; likely veined limestone, possibly low-grade marble (CaCO₃)