Organic (Geological Interest)

Turquoise

Turquoise (Hydrated copper aluminum phosphate, CuAl6(PO4)4(OH)8·4H2O)

Jasper

Silicon Dioxide (SiO2) - a variety of Chalcedony (Cryptocrystalline Quartz)

Gneiss

Gneiss (a type of metamorphic rock)

Amphibolite

Amphibolite

Conglomerate

Conglomerate

Slate

Slate (a fine-grained, foliated metamorphic rock). Mineral composition: Primarily composed of mica minerals (muscovite, chlorite, sericite) and quartz, with minor amounts of hematite, pyrite, and other accessory minerals.

Schist

Schist (various compositions)

Larimar

Pectolite (a variety of pectolite, NaCa2Si3O8(OH))

Marble

Metamorphosed Limestone/Dolomite

Sandstone (likely a river or beach pebble)

Sandstone (a clastic sedimentary rock)

Schist

Schist (various mineral compositions)

Basalt

Basalt

Sandstone (Pebble/Cobble)

Sandstone (arenite is a more precise term for sandstone with less than 15% matrix; this specimen appears to be a lithic or quartz arenite)

Banded Gneiss (with possible weathered sulfide or iron staining)

Gneiss, potentially with iron oxide/hydroxide staining (e.g., limonite) or weathered sulfides

Ruby Fuchsite / Ruby in Fuchsite

Ruby (Al2O3 variety corundum) and Fuchsite (K(Al,Cr)2AlSi3O10(OH)2 - a chromium-rich variety of muscovite mica) in Quartz matrix

Unakite

Epidotized Granite

River Cobble (likely Sandstone or Siltstone type)

Sandstone or Siltstone (common rock types that form river cobbles)

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Banded Gneiss

Gneiss (pronounced "nice")

Sandstone

Sandstone (lithified arenite/wacke)

Quartz

Silicon Dioxide (SiO₂)

Granite Gneiss

Gneiss (derived from granitic protolith)

Chalcedony (Banded/Mottled Variety)

Chalcedony (a cryptocrystalline variety of Quartz, SiO2)

Serpentinite

Serpentinite (a rock composed predominantly of serpentine group minerals)

Granite

Granite (a plutonic rock)

Quartzite

Quartzite

Selenite

Gypsum (CaSO4·2H2O), specifically the crystalline variety Selenite

Schist

N/A (a rock type, not a mineral formula)

Quartzite

Quartzite

Granite

Granite (a common type of Felsic Intrusive Igneous Rock)

Botryoidal Chalcedony with Calcite

Chalcedony (SiO2 with accessory minerals, likely CaCO3)

Granite (likely a river or beach pebble)

Granite (a felsic intrusive igneous rock primarily composed of quartz, feldspar, and mica)

Chert (Jasper or Flint variant)

Chert (composed of microcrystalline quartz, SiO2)

Red Jasper

Jasper (a variety of Chalcedony, SiO₂ with impurities)

Sandstone

Sandstone (Clastic Sedimentary Rock)

Chert / Flint

Silicon dioxide (SiO2)

Quartzite

Quartzite (primarily SiO2)

Chrysoprase

Chalcedony (cryptocrystalline quartz) with nickel inclusions; SiO2

Halite (Rock Salt)

Halite; NaCl (Sodium Chloride)

Laterite

Laterite (no specific mineral formula as it's a rock type)

Sandstone

Sandstone (arenite is a more specific geological term for a clean sandstone, while wacke refers to a dirty sandstone with significant matrix)

Pebble (likely Quartzite or Chert)

Clastic Sediment, potentially composed of SiO₂ (Quartz)