Difference between revisions of "Maxixe"
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Maxixe (pron. Mah-she-she) is the almost [[Sapphire]] color variety of [[Beryl]]. It was discovered in 1917 in the Maxixe mine in the Piaui area south of Arassuahy, Minas Gerais, Brazil. Maxixe owes it's very unstable color due to natural irradiation which causes a color center that is most probably caused in the NO<sub>3</sub> sites. When exposed to sunlight or temperatures above 100° C. it will rapidly loose its color, which can be restored by irradiation (gamma, x-ray or neutron) and annealing.<br /> | Maxixe (pron. Mah-she-she) is the almost [[Sapphire]] color variety of [[Beryl]]. It was discovered in 1917 in the Maxixe mine in the Piaui area south of Arassuahy, Minas Gerais, Brazil. Maxixe owes it's very unstable color due to natural irradiation which causes a color center that is most probably caused in the NO<sub>3</sub> sites. When exposed to sunlight or temperatures above 100° C. it will rapidly loose its color, which can be restored by irradiation (gamma, x-ray or neutron) and annealing.<br /> | ||
− | As of 1973 some dark-blue Beryls started appearing on the market again and research showed that the color was also due to irradiation (artificial), the color center in this case proved to be CO<sub>3</sub>. This new type was named "Maxixe-type" Beryl | + | As of 1973 some dark-blue Beryls started appearing on the market again and research showed that the color was also due to irradiation (artificial), the color center in this case proved to be CO<sub>3</sub>. This new type was named "Maxixe-type" Beryl and like Maxixe it is a very unstable color. The starting color of these stones were yellow or green Beryls.<br /> |
There are also bi-colored Maxixe-type Beryls (yellow/blue) and their color is attributed to artificial irradiation on specimens that have uneven distribution of impurities. | There are also bi-colored Maxixe-type Beryls (yellow/blue) and their color is attributed to artificial irradiation on specimens that have uneven distribution of impurities. | ||
The impurities found in Maxixe and Maxixe-type Beryl are Cs, Zn, Li, Rb, B and high Fe content. | The impurities found in Maxixe and Maxixe-type Beryl are Cs, Zn, Li, Rb, B and high Fe content. |
Revision as of 12:57, 25 October 2006
Maxixe beryl | |
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Chemical composition | Be3Al2(SiO3)6 Beryllium aluminum silicate |
Crystal system | Hexagonal |
Habit | Prismatic |
Cleavage | Poor, basal |
Fracture | Conchoidal to uneven |
Hardness | 7.5 |
Optic nature | Uniaxial - |
Refractive index | 1.579 - 1.592 |
Birefringence | 0.007 |
Dispersion | Low, 0.0014 |
Specific gravity | 2.69 - 2.8 |
Lustre | Vitreous |
Pleochroism | Distinct |
Maxixe (pron. Mah-she-she) is the almost Sapphire color variety of Beryl. It was discovered in 1917 in the Maxixe mine in the Piaui area south of Arassuahy, Minas Gerais, Brazil. Maxixe owes it's very unstable color due to natural irradiation which causes a color center that is most probably caused in the NO3 sites. When exposed to sunlight or temperatures above 100° C. it will rapidly loose its color, which can be restored by irradiation (gamma, x-ray or neutron) and annealing.
As of 1973 some dark-blue Beryls started appearing on the market again and research showed that the color was also due to irradiation (artificial), the color center in this case proved to be CO3. This new type was named "Maxixe-type" Beryl and like Maxixe it is a very unstable color. The starting color of these stones were yellow or green Beryls.
There are also bi-colored Maxixe-type Beryls (yellow/blue) and their color is attributed to artificial irradiation on specimens that have uneven distribution of impurities.
The impurities found in Maxixe and Maxixe-type Beryl are Cs, Zn, Li, Rb, B and high Fe content.