Quartz phyllite
Quartz phyllite, light micrograph
Sample of biotite
Two-mica granite
Rhyolite mountain, Iceland
Granite
Paragneiss
Biotite
Biotite, Tyringham, Massachusetts, USA
Biotite in rock groundmass
Rhyolite
Orthogneiss, light micrograph
Paragneiss, light micrograph
Staurolite crystal, light micrograph
Basaltic dyke rock
Phyllite, deformed metamorphic rock
Graphite
Migmatite
Banded gneiss
Migmatite, light micrograph
Tubular hexagons of quartz
Polished sphere of orbicular jasper
Amphibolite, light micrograph
Childrenite crystal in quartz
Rhyolite, light micrograph
Anatextite gneiss
Granodiorite
Variety of Metamorphic Rocks
Rock strain fringes, light micrograph
Quartz Diorite, LM of thin section
Quartz vein in granite
Fuchsite mineral stone
Polished sphere of ocean jasper
Sample of rose quartz
Dolerite rock crystals, polarised LM
Polished Esterel rhyolite agate
Obsidian flow
Quartz-feldspar porphyry
Rhyolitic geode
Concentric banding in agate
Forbach granite
Snowflake obsidian
Agglomerate rock, polarised LM
Quartz porphyry rough
Brixen granite
Richterite in quartz groundmass
Realgar with grey quartz
Sample of andesite
Andesite
Pyrophyllite
Zoisite in pegmatite groundmass
Mica schist folds, polarised light LM
Sample of basalt
Sample of muscovite
Brazilianite crystals in calcite
Muscovite mineral sample
Mahogany obsidian
Cut and polished septarian nodule
Obsidian
Emeralds
Zeophyllite
Reddish pink apophyllite crystal and basalt groundmass
Heavily weathered kimberlite
Niobite in host rock
Niobite crystal
Pyroclastic rock
Blue Hauyne crystals in lava groundmass
Sanidine on trachyte lava groundmass
Pink-white chabazite in basalt groundmass
Muscovite crystals in rock groundmass
Gold embedded in quartz groundmass
Pyrophyllite and quartz in groundmass
Naturally graphite flakes, light micrograph
Tungstite in quartz groundmass, close-up
Schorl and quartz crystals in groundmass
Olivenite in quartz groundmass, close-up
Bournonite in quartz groundmass, close-up
Granite, light micrograph
Granodiorite, light micrograph
Biotite in calcite groundmass
Val Gardena sandstone
Quartz crystals
Columnar quartzite
graphite
Graphite, New Jersey, USA
Brown granite stone
Jasper
Iris agate
Fairburn agate
Union road agate
Lysite agate
Moss agate
Lake Superior agate
Paint rock agate
Agatised coral
Paul Bunyon plume agate
Siam Siding agate
Plume agate
Fourth of July Butte agate
Agate
Pompon agate
Regency rose agate
Blue Bed thunder egg agate
Priday plume agate
Antelope agate
Sweet home agate
Coyamito agate
Bubble lace agate
Condor agate
Sweetwater agates
Sagenitic agate
Montana moss agate
Frieda thunder egg agate
Succor Creek thunder egg agate
Oregon Beach agates
Omineca agate
Crater agate
Ocean jasper agate
Queensland agate
Jasper breccia rock
Botryoidal chalcedony, close-up