mineral
Quartz (Iron-stained)
Silicon Dioxide (SiO2)
AI-generated identification · may be incorrectHardness: 7 (Mohs scale); Color: Translucent yellowish-brown to tan; Luster: Vitreous to greasy; Crystal Structure: Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
- Hardness
- 7 (Mohs scale)
- Color
- Translucent yellowish-brown to tan
- Luster
- Vitreous to greasy
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Physical properties
Hardness: 7 (Mohs scale); Color: Translucent yellowish-brown to tan; Luster: Vitreous to greasy; Crystal Structure: Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
Formation & geological history
Forms in a wide variety of environments, most commonly in hydrothermal veins and pegmatites. The coloration here is likely due to secondary iron oxide staining or inclusions within the crystal lattice.
Uses & applications
Mainly a collector specimen in this form. High-purity quartz is used in glassmaking, electronics (piezoelectric properties), and as an abrasive. Polished versions are used in jewelry.
Geological facts
Quartz is the second most abundant mineral in Earth's continental crust. When clear and yellow, it is called Citrine, but natural brown/yellow tinting like this is often referred to as 'ferruginous quartz' or 'smoky quartz' depending on the cause of color.
Field identification & locations
Identify in the field by its hardness (will scratch glass easily) and lack of cleavage. Look for the characteristic conchoidal fracture patterns on the edges. Found globally in almost all geological terrains.
