Tourmaline · Variety of Tourmaline
Rubellite
Vivid pink to red elbaite tourmaline
Pink
Red
Optical characteristics
- Ref. index
- 1.614 – 1.666
- Birefringence
- 0.014 – 0.04
- Luster
- Vitreous
- Pleochroism
- Strong Usually strong dichroism; observe along different crystal directions.
- 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.
Madagascar
Madagascar: Ilakaka / Andranondambo region
Major
Modern major source for sapphire, garnet, beryl, quartz, tourmaline and many collector gems.
Mozambique
Mozambique: Montepuez / Alto Ligonha / Cuamba
Major
Major modern source for ruby, garnet, tourmaline and Paraíba-type tourmaline.
Nigeria
Nigeria: Oyo / Ogun / Plateau fields
Major
Important source for tourmaline, sapphire, garnet, beryl and topaz.
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…
Needles Growth Tubes, Rain Inclusions
Under 10x loupe: long thin hollow channels running parallel to each other and to…
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…
Crystals Radiation Halos
Under 10x loupe or microscope: a dark brown, gray, or discolored spherical zone surrounding…
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