Sedimentary (Secondary Classification For A Weathered Mineral Specimen)

Quartz-rich pegmatite (likely feldspar–quartz rock)

Granitic pegmatite; chiefly quartz (SiO₂) and feldspar, with possible mica/iron-oxide staining

Limonite/goethite-rich ironstone (probable)

Limonite, chiefly hydrated iron oxides; commonly goethite, α-FeO(OH), with possible quartz or host-rock inclusions

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Granite Pebble

Granite (composed of Quartz, Feldspar, and Mica)

Limonite (Hydrated Iron Oxide / Bog Iron)

FeO(OH)·nH2O

Polished kambaba jasper

Orbicular stromatolitic jasper; microcrystalline quartz (SiO₂) with chlorite/amphibole-rich inclusions

Limonite (Iron Ore)

Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)

Iron-rich meteorite candidate

Unclassified meteoritic iron–stone material; possible stony-iron meteorite or terrestrial ironstone

Azurite

Azurite (Cu3(CO3)2(OH)2)

Vesicular basalt (possibly weathered amygdaloidal basalt)

Basalt; chiefly plagioclase feldspar, pyroxene, and commonly olivine, with weathering minerals filling vesicles

Limonite

Limonite (Hydrated iron(III) oxide-hydroxide) FeO(OH)·nH2O

Hematite

Hematite (Iron(III) oxide, Fe2O3)

Chert (Brecciated or Veined)

Silicon Dioxide (SiO2)

Brown Chalcedony (Agate/Jasper)

Cryptocrystalline Quartz (SiO2)

Botryoidal Chalcedony (Agate/Carnelian)

Chalcedony (SiO2)

Milky Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Rounded gray-brown cobble, likely weathered sandstone or quartzite

Tentatively quartz-rich sandstone (SiO₂-dominated); exact identification requires hardness and acid tests

Gossanous Sandstone (likely Terrestrial)

Arenite with Iron-Oxide inclusions

Limonite (Ironstone)

Limonite (mixture of hydrated iron oxides, primarily Goethite α-FeO(OH))

Limonite

FeO(OH)·nH2O

Limonite or Ironstone Nodule

Hydrated iron oxide-hydroxide (FeO(OH)·nH2O)

Limonite Nodule

FeO(OH)·nH2O (Hydrated iron oxide-hydroxide)

Limonite

FeO(OH)·nH2O

Vesicular basalt (weathered lava rock)

Basalt, predominantly plagioclase, pyroxene, and minor olivine/iron oxides

Quartz Pebble

Silicon Dioxide (SiO2)

Iron-rich weathered rock or limonite/goethite nodule

Limonite (mixture dominated by goethite, FeO(OH)·nH₂O), possibly with quartz or clay

Quartz pebble

Silicon Dioxide (SiO2)

Granite countertop slab

Granite; primarily quartz, feldspar, and mica (commonly biotite), with accessory amphibole/iron oxides

Likely metallic mineral specimens

Probably native iron or iron oxide/hydroxide material; exact identification requires testing

Ferruginous Siltstone or Mudstone

Ferruginous Siltstone / Goethitic Sandstone

Limonite with Gossan / Iron Ore

Hydrated iron oxide-hydroxide, approximately FeO(OH)·nH2O

Turquoise

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

Limonite

FeO(OH)·nH2O (Hydrated iron oxide-hydroxide)

Limonite (Iron Ore Congcretion)

Limonite (a mixture of hydrated iron(III) oxide-hydroxides, FeO(OH)·nH2O)

Jasper and Mudstone Composite

Silicified Sedimentary Rock / Jasperoid Pebble

Turquoise (possible Dyed Magnesite/Howlite)

CuAl6(PO4)4(OH)8·4H2O

Limonite (Iron Ore)

FeO(OH)·nH2O

Vesicular basalt (possibly weathered scoria)

Basalt; chiefly plagioclase feldspar, pyroxene, and iron-rich minerals

Limonite (Iron Ore)

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

Lunar Highlands Breccia (Meteorite)

Lunar Feldspathic Breccia

Limonite (Ironstone)

Limonite (FeO(OH)·nH2O)

Sandstone

Arenite (SiO2 based with mineral cements)