Sedimentary (With Some Aspects Of Mineral Replacement)

Chert (variously known as Flint or Jasper)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Red Jasper

Red Jasper (variety of Chalcedony, SiO₂)

Granite Gneiss

Gneiss (High-grade metamorphic rock)

Granite Gneiss with Garnet

Garnetiferous Gneiss

Schist

Mica Schist (Variable chemistry, often rich in muscovite and biotite)

Banded Chert (or Banded Jasper)

Silicon Dioxide (SiO2) with Iron Oxide impurities (Hematite/Goethite)

Sandstone Concretion

Clastic sedimentary rock (primarily Quartz SiO2)

Gneiss (with Quartz-Feldspar vein)

Gneiss (high-grade metamorphic rock) containing Quartz (SiO2) and Feldspar (KAlSi3O8 – NaAlSi3O8 – CaAl2Si2O8)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Gneiss Pebble

Gneiss

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).

Granitic Gneiss

Gneiss (High-grade regional metamorphic rock)

Quartz-veined Mudstone or Argillite

SiO2 (Quartz) in Siltstone/Mudstone matrix

Limestone (specifically Dolomitic Limestone)

Calcium Magnesium Carbonate (CaMg(CO3)2)

Chert Nodules (with Gryphaea or Shell inclusions)

Microcrystalline Quartz (SiO2) with Calcitic inclusions

Chert (Tan/Brown)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Chert (Yellow or Brown Jasper)

Microcrystalline Quartz (SiO2)

Chert (often called Flint when dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Pyritized Ammonite

Ammonitida (replaced by Iron Disulfide, FeS2)

Orange Calcite

Calcium Carbonate (CaCO3)

Gneiss (Banded Gneiss)

Gneiss

Ironstone Concretion / Limonite Node

Goethite and Limonite (FeO(OH) nH2O)

Quartz Druze on Matrix

Silicon Dioxide (SiO2)

Petrified Wood

Silicified Wood (SiO2)

Geode (Unopened)

Siliceous Concretion / Geode

Sandstone (likely Arkosic or Quartzose)

Sandstone (SiO2 dominated)

Pyrite

Iron Sulfide (FeS2)

Sandstone

Quartz Sandstone (predominantly)

Banded Gneiss

Gneiss (Metamorphic Rock)

Ferruginous Quartz

Silicon Dioxide with Hematite/Limonite inclusions (SiO2 + Fe2O3)

Chert (specifically Flint or Jasper variant)

Microcrystalline quartz (SiO2)

Agate (Grey Agate Slice)

Microcrystalline Quartz (SiO2)

Gneiss (specifically a weathered or stream-worn specimen)

Gneiss (Foliated Metamorphic Rock)

Agate

Silicon Dioxide / Cryptocrystalline Quartz (SiO2)

Limonite (Yellow Ochre)

Limonite (an amorphous mixture of hydrated iron oxides, primarily FeO(OH)·nH2O)

Red Sandstone

Arenite (Ferruginous Sandstone)

Jasper

Silicon dioxide (SiO2)

Baltic Amber (Butterscotch or Egg Yolk Variety)

Succinite (chemical formula: C10H16O)

Jasper (var. Ocean or Polychrome Jasper)

Silicon Dioxide (SiO2) with iron and mineral inclusions

Chert (specifically White Chert or Novaculite)

Silicon Dioxide (SiO₂)

Chert (variations include Flint or Jasper)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Chert (and associated Sedimentary rocks)

Microcrystalline Silica (SiO2)