Colored gemstone dealer Bill Vance (Vance Gems, Newark, Delaware) showed us some transparent examples of magnesio-axinite, a rare magnesium-dominant member of the axinite group of minerals. Axinite has a general formula of H(CaFe2+MnMg)3(Al2BSi4O16). Gem-quality magnesio-axinite—also known as axinite-(Mg)—is transparent to translucent, with pale blue to pale violet, light brown to light pink, or yellow to golden yellow or orange color (figure 1, left). More intensely colored bluish violet to purple magnesio-axinite tends to have a higher refractive index (1.659–1.681) than lighter-colored pink, purple, or yellow material (1.652–1.668). Magnesio-axinite has a birefringence of 0.010–0.016, strong dispersion, and a Mohs hardness of 5.5. Stones with a blue color component display pale blue to pale violet and pale gray pleochroic colors. Fluorescence is one of the material’s most striking properties—the gem shows a dull red under short-wave ultraviolet light and a vibrant “merthiolate flame color” red under long-wave UV (figure 1, right). We intend to report on the chemistry of this interesting material at a future date.
- Copyrights and Trademarks
- Privacy Notice
- Terms of Use
- Cookie Notice
- Ethics and Compliance
- Transparency in Coverage Rule
- About This Site
© 2002 -
Loading video player...
Colored gemstone dealer Bill Vance (Vance Gems, Newark, Delaware) showed us some transparent examples of magnesio-axinite, a rare magnesium-dominant member of the axinite group of minerals. Axinite has a general formula of H(CaFe2+MnMg)3(Al2BSi4O16). Gem-quality magnesio-axinite—also known as axinite-(Mg)—is transparent to translucent, with pale blue to pale violet, light brown to light pink, or yellow to golden yellow or orange color (figure 1, left). More intensely colored bluish violet to purple magnesio-axinite tends to have a higher refractive index (1.659–1.681) than lighter-colored pink, purple, or yellow material (1.652–1.668). Magnesio-axinite has a birefringence of 0.010–0.016, strong dispersion, and a Mohs hardness of 5.5. Stones with a blue color component display pale blue to pale violet and pale gray pleochroic colors. Fluorescence is one of the material’s most striking properties—the gem shows a dull red under short-wave ultraviolet light and a vibrant “merthiolate flame color” red under long-wave UV (figure 1, right). We intend to report on the chemistry of this interesting material at a future date.
- Copyrights and Trademarks
- Privacy Notice
- Terms of Use
- Cookie Notice
- Ethics and Compliance
- Transparency in Coverage Rule
- About This Site
© 2002 -
Loading video player...
