mineral

Chert or chalcedony fragment

Microcrystalline quartz (SiO₂), likely translucent chert/chalcedony

AI-generated identification · may be incorrect

Pale honey-yellow, translucent, with a waxy-to-glassy luster and conchoidal-looking fracture; hardness about 6.5–7 Mohs, no cleavage, trigonal quartz structure, specific gravity ~2.60. The bright spots may be polish or reflective fracture surfaces.

Identified August 20, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities or replaces carbonate sediments; commonly Cenozoic to older, depending on host strata. The Yemen location is geologically compatible with widespread sedimentary chert and silica-rich vein material.

Uses & applications

Common chert is used historically for sharp tools and occasionally aggregate; attractive translucent chalcedony is cut, polished, or used in inexpensive jewelry and specimen collecting.

Geological facts

Its translucent yellow color can result from iron staining or microscopic inclusions. It may resemble yellow calcite, but quartz is much harder and will not usually be scratched by a steel knife.

Field identification & locations

Identify with a steel scratch test: quartz/chalcedony should resist scratching, while calcite scratches readily; quartz also does not fizz in dilute acid. A definitive ID requires hardness, streak, and ideally microscopy or Raman/XRD testing.