Metamorphic Or Sedimentary Depending On Local Grade

Quartz (Milky or Clear Quartz fragment)

Silicon Dioxide (SiO2)

Gneiss

Metamorphic Gneiss (High-grade regional metamorphism)

Kyanite

Kyanite (Al2SiO5)

Dark metamorphic rock, likely schist or phyllite

Quartz–mica schist/phyllite; chiefly quartz, mica, and feldspar

Ferruginous Sandstone (with Iron Oxide staining)

Clastic Sedimentary Rock - Quartz Arenite/Wacke

White marble (likely calcite marble)

Calcite-rich marble, chiefly CaCO₃

Quartzite Pebble

Metamorphic Quartzite

Druzy Quartz on Host Rock

Silicon Dioxide (SiO2) with various iron-oxide inclusions

Ironstone Concretion

Ironstone (Limonite/Goethite Concretion)

Pink Feldspar (Orthoclase)

Orthoclase Feldspar (KAlSi3O8)

Green Slate or Metamorphic Rock

Metamorphic rock (chlorite/actinolite-bearing)

Schist

Schist

Polished gneiss or migmatitic gneiss cobble

Banded quartz–feldspar–biotite gneiss; compositionally possibly migmatitic

Generic Rock / River Pebble

Lithic fragment / Quartzite pebble

Schist

Schist (various mineral compositions)

Possible graphite-bearing schist

Graphitic mica schist; predominantly quartz, mica, and graphite

Greenschist

Greenschist facies rock

Greenstone (likely chlorite-rich metamorphic rock)

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

Chert Nodule

Chert (SiO2)

Likely serpentinite (serpentine-rich rock)

Serpentinite, composed mainly of serpentine-group minerals (e.g., antigorite, lizardite, or chrysotile)

Milky Quartz

Silicon Dioxide (SiO2)

Magnetite / Iron Ore

Magnetite (Fe3O4)

Dark metamorphic cobble, likely slate or phyllite

Foliated metamorphic rock, probably carbonaceous slate/phyllite; exact identification requires testing

Chalcedony (Pancawarna / Bacan / Red Chalcedony Agate Ring)

Silicon dioxide (SiO2)

Banded Mudstone (Siltstone Pebble)

Siltstone / Argillite (Fossiliferous Mudstone)

Rounded gray stone, likely slate or fine-grained sandstone

Probable slate (low-grade metamorphosed shale) or lithic sandstone; exact identification requires testing

Vesicular Basalt with Epidote/Amygdaloidal Basalt

Amygdaloidal Basalt (Mg, Fe)2SiO4 + Ca2(Al, Fe)3(SiO4)3(OH)

Glacial Erratic (Sandstone/Quartzite)

Glacial Erratic specimen (likely Orthoquartzite or Feldspathic Sandstone)

Mixed Gravel and Pebbles

Polylithic Alluvial Aggregate

Phyllite

Phyllite (Intermediate grade metamorphic rock)

Stony-Iron Meteorite (likely Mesosiderite or Ordinary Chondrite)

Meteorite (Silicate-Metal Matrix)

Likely polished tiger’s-eye with dark matrix

Quartz (SiO₂) with fibrous crocidolite-derived inclusions; possibly an iron-rich jasper or other dark host rock

Pale greenish quartz-bearing rock, possibly serpentine or altered feldspar

Tentatively serpentinite-related rock (serpentine-group minerals) or altered granitic material; identification is uncertain from the photograph

Sodalite

Sodalite (Na8(Al6Si6O24)Cl2)

Epidote–garnet schist (probable)

Epidote + garnet + quartz/feldspar mica schist; garnet may be almandine–grossular series

Kyanite

Kyanite (Al2SiO5)

Generic Pebble / Rock Fragment

Lithic fragment / Weathered rock pebble

Biotite-rich schist (probable mica schist)

Mica schist; predominantly quartz, biotite, and feldspar

Weathered iron-stained quartzite or sandstone cobble

Quartzite (quartz, SiO₂), possibly ferruginous sandstone

Jasper

Chalcedony (SiO2)

Graphite-rich schist (probable graphite flake)

Graphite (C) in graphitic schist; commonly with quartz, mica, and feldspar

Milky Quartz (with Iron staining)

Silicon Dioxide (SiO2)