Quartz
Smoky Quartz
Brown to smoky gray quartz
Brown
Gray
Optical characteristics
- Ref. index
- 1.544 – 1.553
- Birefringence
- 0.009
- Luster
- Vitreous
- Pleochroism
- Weak to none Usually weak to none.
- Fluorescence
- Usually inert to weak.
Source localities
Brazil
Brazil: Minas Gerais / Paraíba / Bahia
Major
Major source for beryl, tourmaline, quartz, topaz, chrysoberyl and rare minerals.
United Kingdom
Scotland: smoky quartz localities
Notable
Known historically for cairngorm smoky quartz.
United States
USA: major gem fields
Notable
Diverse sources for turquoise, tourmaline, opal, sapphire, topaz, red beryl and rare minerals.
Switzerland
Switzerland: alpine quartz localities
Notable
Known for rock crystal and alpine minerals.
Enhancement & treatment
Inclusions & features
Zoning Color Zoning
Under 10x loupe in immersion: bands or patches of deeper or lighter color arranged…
Crystals Crystal Inclusions
Under 10x loupe: solid, well-formed mineral crystals trapped inside the host gem. They may…
Fractures Feathers and Fractures
Under 10x loupe: irregular internal surfaces that catch light and appear bright, wing-like, or…
Fractures Fingerprint Inclusions
Under 10x loupe: curved or wavy lines of tiny dots forming patterns that look…
Crystals Negative Crystals
Under 10x loupe: an empty cavity that has the geometric shape of the host…
Clouds Pinpoint Clouds
Under 10x loupe: concentrations of extremely tiny bright dots that individually are too small…
Multiphase Two-Phase Inclusions
Under 10x loupe: a transparent irregular cavity containing both a liquid phase and a…
Instruments used
10x Loupe
Your most-used instrument, start every examination here
Polariscope
Determines single vs. double refraction, quick and conclusive
Refractometer
Measures refractive index, the backbone of gem identification
UV Lamp, Long Wave and Short Wave
Fluorescence exposes treatments, synthetics, and origin