Vesicular basalt (likely scoria or weathered pumice)
Vesicular basalt; chiefly plagioclase, pyroxene, olivine, and volcanic glass
igneous
Category
Sedimentary (Volcanic)
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Reddish weathered rock, possibly jasper or iron-rich chert
Microcrystalline quartz (SiO₂), if jasper/chert; abundant iron oxides such as hematite/goethite
mineral
Vesicular basalt (likely scoria)
Vesicular basalt; predominantly plagioclase, pyroxene, and possibly olivine
igneous
Agate
Silicon Dioxide (Chalcedony), SiO2
sedimentary
Rounded basalt pebble
Basalt; fine-grained mafic volcanic rock composed mainly of plagioclase and pyroxene, commonly with olivine
igneous
Jasper
Silicon Dioxide (SiO2) with impurities
sedimentary
Agate Bookend / Quartz Geode
Silicon Dioxide (SiO2)
mineral
Pumice
Pumice (Amorphous volcanic glass)
Igneous
Yellow Jasper / Chalcedony
Silicon Dioxide (SiO2) with iron inclusions
mineral
Agate / Chalcedony
Silicon dioxide (SiO2)
mineral
Rhyolite
Rhyolite (Extrusive Igneous Rock)
igneous
Quartz geode
Microcrystalline and crystalline quartz, SiO₂, likely with chalcedony and iron-oxide staining
mineral
Quartz Druzy (on Matrix)
Silicon Dioxide (SiO2)
mineral
Banded Agate
Chalcedony (Silicon Dioxide, SiO2)
sedimentary
Agate
Silicon dioxide (chalcedony variety), SiO2
sedimentary
Educational Geologic Collection
Mixed Mineral and Rock Collection (Various compositions)
mineral
Reddish-brown river pebble
Likely ferruginous sandstone or weathered reddish volcanic rock; exact identification requires a fresh surface and tests
sedimentary
Red Jasper
Microcrystalline Quartz (SiO2 with Iron Oxide impurities)
sedimentary
Jasper (Mookaite / Brecciated Jasper)
Microcrystalline Quartz (SiO2 with iron oxide inclusions)
sedimentary
Hematite
Hematite (Fe2O3)
mineral
Druzy Quartz on Matrix
Silicon Dioxide (SiO2)
mineral
Quartz Druzy
Crystalline Silicon Dioxide (SiO2)
mineral
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Petrified Wood and Mixed Rocks
Silicified Wood (SiO2)
fossil
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Red Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
sedimentary
Petrified Wood
Silicified Wood (SiO2)
mineral
Jasper with Iron Staining
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Petrified Wood
Silicified wood (primarily SiO2)
sedimentary
Petrified Wood
Silicified Wood (primarily Chalcedony or Quartz, SiO2)
sedimentary
Jasper and Agate Mix
Silicon dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Orbicular jasper (ocean jasper-like jasper)
Microcrystalline quartz (SiO₂), commonly with iron-oxide and clay inclusions
sedimentary
Polychrome jasper
Microcrystalline quartz (chalcedony), SiO₂, colored by iron oxides and other inclusions
sedimentary
Polished picture jasper slab
Silicified/lithified microcrystalline quartz (chalcedony), commonly with iron-oxide and clay-mineral bands
sedimentary
Red Jasper
Jasper (Silicon Dioxide with Iron Oxide inclusions), SiO2
sedimentary
Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Tumbled brown chalcedony (likely jasper or chert)
Microcrystalline quartz, SiO₂; opaque varieties are commonly called jasper or chert
mineral
Petrified Wood
Silicified Wood (SiO2)
fossil
Petrified Wood
Silicified Wood (SiO2)
fossil
Limonite (Iron Ore)
Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)
sedimentary
Petrified Wood
Silicified Wood (primarily SiO2)
mineral
Yellow Chalcedony or River Jasper
Silicon Dioxide (SiO2)
sedimentary