Iron-stained Quartzite

Physical Properties

Hardness: 7 on Mohs scale; Color: yellowish-brown to orange-tan with translucent patches; Luster: vitreous to waxy; Crystal structure: trigonal (microcrystalline); Cleavage: none, exhibits conchoidal or irregular fracture.

Formation & Geological History

Formed from the regional or contact metamorphism of quartz-rich sandstone. The yellow-brown coloration is a result of iron oxide (limonite) leaching into the micro-fractures of the stone during weathering.

Uses & Applications

Large-scale deposits are used for construction aggregate and railway ballast. Aesthetic pieces like this are often kept as garden stones or used in lapidary work for tumbled stones.

Geological Facts

Quartzite is so durable that it can outlast the surrounding softer rock in mountainous terrain, often forming the peaks of ridges. The staining in this specimen acts as a natural pigment.

Field Identification & Locations

Identified by its high hardness (it will scratch glass) and its granular, sugary texture on fresh breaks. It is commonly found in riverbeds and glacial deposits.

Identified on: 4/27/2026

Mode: Standard