Sedimentary And Igneous (Mixed)

Gneiss

Gneiss

Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Biotite Mica

Biotite, K(Mg,Fe)3AlSi3O10(F,OH)2

Quartz

Quartz (SiO2 - Silicon Dioxide)

Quartz

Quartz (SiO₂ - Silicon Dioxide)

Quartz

Quartz (Silicon Dioxide - SiO2)

Quartz

Silicon Dioxide (SiO₂)

Jasper and Basalt Mix (Dark Chert/Basalt River Pebble)

Silicon Dioxide (SiO2) or Mafic extrusive igneous rock

Mica Group Minerals

There isn't a single scientific name as 'Mica' refers to a group of phyllosilicate minerals. Common scientific names include Muscovite (KAl₂ (AlSi₃O₁₀)(OH)₂), Biotite (K(Mg,Fe)₃AlSi₃O₁₀(OH)₂), Phlogopite (KMg₃AlSi₃O₁₀(OH)₂), and Lepidolite (K(Li,Al)₃(Al,Si,Rb)₄O₁₀(F,OH)₂).

Milky Quartz

Quartz (SiO2)

River Cobble (likely Basalt or Chert)

Siliceous River Rock / Microcrystalline Quartz / Mafic Igneous

Black Chert

Chert (microcrystalline quartz)

Pink Opal / Peruvian Opal

Hydrated amorphous silicon dioxide (SiO2·nH2O)

Pyrite

Pyrite (Iron Disulfide), FeS2

Quartz

Silicon dioxide (SiO₂)

Red Jasper

Jasper (a variety of Quartz, SiO2)

Weathered granite (feldspathic, iron-stained granite)

Granite; primarily quartz, potassium feldspar, plagioclase feldspar, and minor mica/amphibole. Exact identification is uncertain from a single photograph.

Weathered granite or granitic pegmatite cobble

Granite/granitic rock, composed mainly of quartz (SiO₂), feldspar, and minor biotite or other dark minerals; the reddish-brown areas may be iron-oxide staining or weathered accessory minerals

Quartz (likely Clear Quartz or Rock Crystal)

Quartz (SiO2)

Pebble (likely a type of sandstone or quartzite pebble)

Clastic Sediment (specifically, a rudite-sized clast). If the pebble is composed of a specific rock type, its scientific name would be that rock type (e.g., 'Quartzite pebble', 'Granite pebble', 'Chert pebble'). Given its appearance, it is likely a metamorphic quartzite pebble or a hard sandstone pebble.

Apatite

Apatite Group (e.g., Fluorapatite Ca5(PO4)3F, Chlorapatite Ca5(PO4)3Cl, Hydroxylapatite Ca5(PO4)3(OH))

Rock Crystal Quartz

Quartz (SiO₂)

Nephrite Jade

Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2)

Gneiss (specifically a Banded Gneiss pebble)

Gneiss (High-grade Regional Metamorphic Rock)

Crystal Quartz Beads (likely Clear Quartz)

Quartz (SiO₂)

Fluorite

Fluorite (Calcium Fluoride, CaF2)

Fluorite in Matrix

Fluorite (CaF2) within a host rock matrix

Gneiss

Gneiss (Metamorphic rock of variable composition, typically SiO2 rich)

Jasper

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

Laterite

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

Obsidian and Green Calcite

Volcanic Glass and Calcium Carbonate (CaCO3)

Quartz

Quartz (SiO2 - Silicon Dioxide)

Gneiss

Gneiss (High-grade metamorphic rock)

Muscovite Mica

Muscovite (Potassium Aluminum Silicate Hydroxide Fluoride), KAl2(AlSi3O10)(OH,F)2

Orthoclase Feldspar

Orthoclase (KAlSi3O8)

Biotite Mica

Biotite (K(Mg,Fe)3AlSi3O10(F,OH)2)

Gneiss

Gneiss (High-grade regional metamorphic rock)

Quartz (River Pebble)

Quartz (SiO₂ - Silicon Dioxide)

Peridot and Citrine Gemstones (in a ring setting)

Peridot (Olivine: (Mg,Fe)2SiO4), Citrine (Quartz: SiO2)

Weathered pegmatite or feldspar-rich granite fragment

Granitic pegmatite, composed mainly of potassium feldspar and quartz, with minor mica; exact identification is uncertain from the photograph

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)

Quartz (chalcedony variety) or Limestone with Quartz Veins

SiO2 (for Quartz/Chalcedony); CaCO3 (for Limestone)