Feldspar
Amazonite
Green to blue-green feldspar
Blue
Green
Optical characteristics
- Ref. index
- 1.518 – 1.572
- Birefringence
- 0.005 – 0.01
- Luster
- Vitreous to pearly
- Pleochroism
- Variable Variable depending on transparency, orientation, and variety.
- Fluorescence
- Variable to inert.
Source localities
Russia
Russia: Ural Mountains / Siberia
Legendary
★ Top Source
Classic source for alexandrite, demantoid, diamond and nephrite.
Madagascar
Madagascar: Ilakaka / Andranondambo region
Major
Modern major source for sapphire, garnet, beryl, quartz, tourmaline and many collector gems.
United States
USA: major gem fields
Notable
Diverse sources for turquoise, tourmaline, opal, sapphire, topaz, red beryl and rare minerals.
Inclusions & features
Fractures Centipede Inclusions
Under 10x loupe: rows of short stress fractures between alternating feldspar layers, arranged perpendicular…
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…
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
Dichroscope
Reveals pleochroism, instantly eliminates singly-refractive stones
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