Tourmaline · Variety of Tourmaline
Canary Tourmaline
Vivid canary yellow to golden yellow; predominantly from African sources
Canary Yellow
Yellow
Optical characteristics
- Ref. index
- 1.62 – 1.64
- Birefringence
- 0.018 – 0.04
- Luster
- Vitreous
- Pleochroism
- Strong Strong dichroism: deep canary yellow to pale straw-yellow.
- Fluorescence
- Inert.
Source localities
Tanzania
Tanzania: Merelani Hills
Significant
Sole source of tanzanite worldwide; also produces tsavorite, ruby, sapphire and rare collector gems.
Brazil
Brazil: Minas Gerais / Paraíba / Bahia
Significant
Major source for beryl, tourmaline, quartz, topaz, chrysoberyl and rare minerals.
Nigeria
Nigeria: Oyo / Ogun / Plateau fields
Significant
★ Top Source
Important source for tourmaline, sapphire, garnet, beryl and topaz; primary source of canary tourmaline.
Mozambique
Mozambique: Montepuez / Alto Ligonha / Cuamba
Significant
Major modern source for ruby, garnet, tourmaline and Paraíba-type tourmaline.
Enhancement & treatment
Inclusions & features
Needles Growth Tubes, Rain Inclusions
Under 10x loupe: long thin hollow channels running parallel to each other and to…
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 Fingerprint Inclusions
Under 10x loupe: curved or wavy lines of tiny dots forming patterns that look…
Instruments used
Refractometer
Measures refractive index, the backbone of gem identification
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
UV Lamp, Long Wave and Short Wave
Fluorescence exposes treatments, synthetics, and origin