Mineral, Often A Rock Given Its Aggregate Nature

Agate (Polished Nodule)

Agate (Silicon Dioxide, SiO2)

Sandstone

Arenite (primarily SiO2)

Epidote in Basalt

Epidotized Basalt (Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH) in Mafic Igneous Host)

Polygenetic Breccia

Clastic Breccia (containing lithic fragments in a fine-grained matrix)

Red Jasper

Silicon Dioxide with Iron Oxide (SiO2)

Tiger's Eye

Silicon dioxide (SiO2) with fibrous inclusions of crocidolite

Limestone with Quartz/Calcite Veins

Sedimentary Limestone (CaCO3 with SiO2 or CaCO3 intrusions)

Yellow Quartz Pebble

Silicon Dioxide (SiO2)

Sparkling Druzy Quartz on Matrix

Silicon Dioxide (SiO2) with iron oxide inclusions

Turquoise and Hematite

Turquoise (CuAl6(PO4)4(OH)8·4H2O) and Hematite (Fe2O3)

Serpentinite

Serpentinite (composed primarily of minerals in the Serpentine group)

Limonitic Sandstone with Inclusion

Limonitic Quartz Sandstone (primarily SiO2 with FeO(OH)·nH2O)

Limestone

Calcium Carbonate (CaCO3)

Sandstone (lithic wacke/arenite)

Clastic sedimentary rock (primarily SiO2)

Banded Sandstone

Arenite with Liesegang banding (primarily SiO2 with FeO(OH) impurities)

Basalt with Epidote Veins

Mafic Igneous Rock (Basalt)

Milky Quartz (Water-Worn Pebble)

Silicon Dioxide (SiO2)

Amygdaloidal Basalt

Amygdaloidal Basalt with Secondary Infilling (e.g., Agate, Quartz, or Zeolite)

Turquoise

Turquoise (Hydrated phosphate of copper and aluminium) CuAl6(PO4)4(OH)8·4H2O

Amethyst (Tumbled)

Amethyst (Silicon Dioxide, SiO2 + Fe4+)

Banded Quartz

Silicon Dioxide (SiO2)

Chalcedony (Botryoidal)

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Basalt

Mafic Volcanic Rock (composed mainly of Plagioclase, Pyroxene, and Olivine)

Turquoise in Matrix

Hydrous phosphate of copper and aluminium, CuAl6(PO4)4(OH)8·4H2O

Jasper

Jasper (Silicon Dioxide, SiO2)

Fire Opal (in Matrix)

Hydrated Silica (SiO2·nH2O)

Chert (Tan/Yellow variety)

Microcrystalline quartz (SiO2)

Basalt

Extrusive mafic igneous rock

Milky Quartz with inclusions

Quartz (Silicon Dioxide, SiO2)

Chert / River Pebble

Silicon Dioxide (SiO2)

Included Quartz Beads (likely Phantom Quartz or Garden Quartz)

Quartz (SiO2) with various mineral inclusions

Granite

Granite (a broadly defined plutonic igneous rock, often more specifically classified as quartz monzonite or granodiorite based on precise mineral percentages)

Granite

Plutonic felsic rock (Quartz, Feldspar, Mica)

Orthoclase Feldspar

KAlSi3O8 (Potassium Aluminum Silicate)

Lazulite

Lazulite (Mg,Fe2+)Al2(PO4)2(OH)2

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily Quartz - SiO2)

Scoria

Vesicular Basalt / Scoria (Mafic silicate rock)

Chert (specifically Iron-stained River Cobble)

Silicon Dioxide (SiO2)

Gneiss (Metamorphic Cobble)

Gneiss (High-grade Regional Metamorphic Rock)

Sandstone (Weathered Pebble)

Arenite (SiO2 primarily)

Chert (Nodule)

Microcrystalline or Cryptocrystalline Quartz (SiO2)