Organic Gemstone (Not A Mineral)

Pearl

Nacre (aragonite, CaCO₃, in a conchiolin matrix)

Pearl necklace

Pearl: biogenic calcium carbonate, primarily aragonite (CaCO₃), in a conchiolin matrix

Pearl

Calcium Carbonate (CaCO3) + Conchiolin

Pearl

Organic gemstone (Calcium carbonate / CaCO3 + Conchiolin)

Pearl

Calcium carbonate (CaCO3) + organic conchiolin

Amber (likely Baltic amber)

Fossilized tree resin; chiefly polymerized diterpenoid resin (succinite)

Limonite

FeO(OH)·nH2O

Red coral (likely precious coral)

Corallium sp.; calcium-carbonate skeleton, primarily calcite

Obsidian

Obsidian (Volcanic Glass, ~70% SiO2)

Amber

Succinite (specifically for Baltic amber); approximate formula C10H16O

Moss Agate

Silicon Dioxide (Chalcedony variety) with green hornblende or chlorite inclusions - SiO2

Freshwater Pearl

Calcium Carbonate (CaCO3) - Aragonite/Calcite organic composite

Amber beads

Amber, fossilized plant resin; largely polymerized terpenoid resin (not a mineral)

Fossil gastropod (snail shell)

Fossilized gastropod; original shell likely aragonite or calcite (CaCO₃), now partly mineral-replaced

Amber with dark mineral/organic inclusions

Fossilized plant resin (amber; chiefly polymerized diterpenoid resin)

Limonite Geode / Ironstone Nodule

Hydrated Iron Oxide Hydroxide (FeO(OH)·nH2O)

Pearl

Calcium carbonate with conchiolin (CaCO3)

Amber and Tumbled Stones

Fossilized Tree Resin (Succinite)

Pearl

Organic Mineral (CaCO3 with conchiolin)

Pearl (incorporated into jewelry)

Aragonite and Calcite (CaCO3)

Pearl

Calcium Carbonate (Aragonite) with Conchiolin; formula: CaCO3

Fossil Coral / Crinoid Stem section

Anthozoa / Crinoidea fossil

Blue Apatite

Calcium Phosphate (Ca5(PO4)3(F,Cl,OH))

Greenstone (likely chlorite-rich metamorphic rock)

Greenschist; commonly composed of chlorite, actinolite, and epidote, with possible albite

Sandstone or Quartzite with algae

Unknown specific, largely SiO2 with biological growth

Polished Black Obsidian

Volcanic Glass (70-75% SiO2)

Obsidian

Amorphous volcanic glass (70-75% SiO2)

Amber (possibly rough amber)

Fossilized tree resin; chemically a complex organic mixture, commonly classified as succinite when Baltic in origin

Amber

Succiniferous fossil resin (C10H16O)

Amber

Fossilized Tree Resin

Snowflake Obsidian

Volcanic Glass (SiO2 + impurities)

Amber in Matrix

Succinite (Carbon-based organic polymer)

Polished black stone, likely black obsidian

Obsidian, volcanic glass; primarily silica-rich SiO₂ with minor feldspar, iron, and magnesium

Obsidian

Volcanic Glass (SiO2 with impurities)

Pearl strand

Nacreous pearl, primarily aragonite (CaCO₃) with conchiolin protein

Limonite

FeO(OH)·nH2O

Amber (likely a small rough amber piece)

Fossilized plant resin; amber is an organic mineraloid, not a crystalline mineral

Likely coal (possibly anthracite)

Coal, composed chiefly of carbon-rich organic matter; rank cannot be confirmed from the photograph

Amber

Succinite (specifically for Baltic amber); approximate formula C10H16O

Pearl

Aragonite (CaCO3 with conchiolin)

Limonite

FeO(OH)·nH2O

Pearl

Calcium Carbonate (Aragonite/Calcite) with Conchiolin, CaCO3