BH250-224
Title
BH250-224
Subject
Quartzite
Quartzite from Jack Hills of Western Australia.
Quartzite from Jack Hills of Western Australia.
Description
Major Minerals: quartz, muscovite, biotite
Minor Mineral: zircon
Mineralogy Comments: one of oldest zircons in world (4.4 billion years)
Quartzite is a hard, durable metamorphic rock formed by the recrystallization of quartz-rich sandstone under elevated temperature and pressure. During metamorphism, original sand grains are fused into a dense, interlocking mosaic of quartz crystals, giving quartzite its characteristic strength and resistance to weathering. In hand sample, quartzite typically appears light colored—ranging from white to gray or pink—and commonly fractures across grains rather than around them, a key feature that distinguishes it from its sedimentary precursor.
Mineralogically, quartzite is dominated by quartz, with minor amounts of muscovite and biotite mica that may impart a subtle sheen or weak foliation in some specimens. Accessory minerals such as zircon may be present in trace amounts, yet they are of exceptional scientific importance. In most quartzites, zircon grains are detrital, inherited from the original sandstone and preserved through metamorphism, making them valuable recorders of ancient crustal history.
A particularly famous occurrence of quartzite is found in the Jack Hills of Western Australia, within Australia. These quartzites contain detrital zircon grains that are among the oldest known materials on Earth, with ages reaching up to about 4.4 billion years. These zircons predate most preserved rocks and provide rare insight into the earliest crust of the planet, suggesting that continental crust—and possibly liquid water—existed very early in Earth’s history. Their survival through multiple cycles of erosion, deposition, and metamorphism highlights both the resilience of zircon and the complex recycling processes of Earth’s crust.
Quartzite from the Jack Hills is therefore more than a simple metamorphic rock; it is a geological archive of deep time. The combination of a quartz-dominated mineral assemblage, minor mica, and the presence of ancient zircon grains makes it an exceptional teaching and research material for understanding sedimentary provenance, metamorphic processes, and the earliest chapters of Earth history. This particular sample was collected by John Goodge, further emphasizing its value as both a scientific specimen and an educational resource.
Minor Mineral: zircon
Mineralogy Comments: one of oldest zircons in world (4.4 billion years)
Quartzite is a hard, durable metamorphic rock formed by the recrystallization of quartz-rich sandstone under elevated temperature and pressure. During metamorphism, original sand grains are fused into a dense, interlocking mosaic of quartz crystals, giving quartzite its characteristic strength and resistance to weathering. In hand sample, quartzite typically appears light colored—ranging from white to gray or pink—and commonly fractures across grains rather than around them, a key feature that distinguishes it from its sedimentary precursor.
Mineralogically, quartzite is dominated by quartz, with minor amounts of muscovite and biotite mica that may impart a subtle sheen or weak foliation in some specimens. Accessory minerals such as zircon may be present in trace amounts, yet they are of exceptional scientific importance. In most quartzites, zircon grains are detrital, inherited from the original sandstone and preserved through metamorphism, making them valuable recorders of ancient crustal history.
A particularly famous occurrence of quartzite is found in the Jack Hills of Western Australia, within Australia. These quartzites contain detrital zircon grains that are among the oldest known materials on Earth, with ages reaching up to about 4.4 billion years. These zircons predate most preserved rocks and provide rare insight into the earliest crust of the planet, suggesting that continental crust—and possibly liquid water—existed very early in Earth’s history. Their survival through multiple cycles of erosion, deposition, and metamorphism highlights both the resilience of zircon and the complex recycling processes of Earth’s crust.
Quartzite from the Jack Hills is therefore more than a simple metamorphic rock; it is a geological archive of deep time. The combination of a quartz-dominated mineral assemblage, minor mica, and the presence of ancient zircon grains makes it an exceptional teaching and research material for understanding sedimentary provenance, metamorphic processes, and the earliest chapters of Earth history. This particular sample was collected by John Goodge, further emphasizing its value as both a scientific specimen and an educational resource.
Coverage
Location: Jack Hills, Western Australia, Australia
Creator
Bereket Haileab
Source
From the rock collection of Bereket Haileab. Sample 224. Housed at Carleton College in Minnesota.
Contributor
John Goodge
Type
Thin section
Relation
Collection
Citation
Bereket Haileab, “BH250-224,” BH250 Mineralogy Teaching Collection, accessed August 30, 2026, https://bereket-haileab.geology.sites.carleton.edu/items/show/295.