Quartz (specifically Milky Quartz/Quartzite)

Hardness: 7 on the Mohs scale. Color: White to off-white, translucent with yellowish-brown iron staining. Luster: Vitreous (glassy) to greasy. Crystal structure: Trigonal/Hexagonal. Cleavage: None (conchoidal fracture). Specific gravity: 2.65.

Formed through the crystallization of magma or by precipitation from hydrothermal veins. It is found in igneous, metamorphic, and sedimentary environments globally. While the mineral is found in rocks of all geological ages, smooth river-worn specimens like this are often shaped during the Quaternary period.

Used extensively in the glass-making industry, as an abrasive, in electronics (due to piezoelectric properties), construction aggregates, and as gemstones or decorative palm stones in the lapidary arts.

Quartz is the second most abundant mineral in Earth's continental crust. Its name is derived from the German word 'Quarz', which likely came from a Slavic word meaning 'hard'. It is famous for being used in 'quartz movements' in watches because it vibrates at a very precise frequency when an electric current is applied.

Identify in the field by its inability to be scratched by a steel knife (H>5.5) and its lack of cleavage. This specific specimen is likely a water-tumbled river stone or a machine-polished palm stone. It is commonly found in riverbeds, glacial deposits, and mountain outcrops. For collectors, it is a primary indicator mineral for the presence of other valuable minerals in hydrothermal vein systems.