_BUQARI_
Shiny_Rock
- Joined
- Dec 3, 2011
- Messages
- 164
I was just searching the internet for some Brazilian Emerald information ..
And I found a "new" type of gemstone ... Emerald Corundum?
Something else than Green Sapphire, huh?
"The extremely rare Oriental Emerald, a designation now in disuse, is a green corundum. The Beryl Emerald is found in South America and is the variety which made famous the Muso mines in Colombia which today are closed. In all cases the coloring matter is chromium.
The discovery of corundum emeralds has been reported in the state of Goiaz but no further details are available.
The emerald occurs in association with basic rock (talcum schist) in Itaberai in the Serra das Lages in the state of Goiaz. The alluviums of this region have an extension of several kilometers.
The emerald appears in the state of Minas Gerais in the regions of Conceicao, Itabira and Ferro where it is found in mica schist cut by pegmatite veins.
Two regions in the state of Baia at present produce emeralds, Vila Nova in the municipality of Conquista, near the Rio Gaviao, and Serra das Eguas in the municipality of Brumado. In these localities they are found in veins of magnesite, constituted of large rhombohedrons of the magnesite itself and of quartz, emerald, tourmaline, topaz, etc. This type of occurrence is very similar to that found in Colombia, the leading producing district of which at present in Chivor.
In the Serra das Eguas there are alluviums with emerald deposits covering an area of 2,000 meters ,by 200 meters. The present operations however are limited to a zone of only 200 meters by 300 meters, partly in the veins, but for the most part in the alluvial deposits. It is possible to prospect these deposits by means of a line of shafts following the maximum declivity. Excellent gems were discovered in this manner at Brumado in the state of Baia.
Ordinary Brazilian emeralds range from 50 milreis to 200 milreis a gram while cut stones vary from 50 milreis to 500 milreis a carat, Eppler however mentions prices up to 10,000 milreis a carat for some stones.
Corundum is an anhydrous aluminum with a hardness of 9, density of 4, and a refraction index of 1.765. It occurs in short bipyramidal prisms. The blue variety is known as sapphire or "engineers' stone" the coloring of which is due to the presence of iron and titanium, while the red stone is the ruby or "lawyers' stone", the coloring of which is attributed to the chromium element ."
http://www.farlang.com/gemstones/jobim-mineral-wealth/page_022
And I found a "new" type of gemstone ... Emerald Corundum?
Something else than Green Sapphire, huh?
"The extremely rare Oriental Emerald, a designation now in disuse, is a green corundum. The Beryl Emerald is found in South America and is the variety which made famous the Muso mines in Colombia which today are closed. In all cases the coloring matter is chromium.
The discovery of corundum emeralds has been reported in the state of Goiaz but no further details are available.
The emerald occurs in association with basic rock (talcum schist) in Itaberai in the Serra das Lages in the state of Goiaz. The alluviums of this region have an extension of several kilometers.
The emerald appears in the state of Minas Gerais in the regions of Conceicao, Itabira and Ferro where it is found in mica schist cut by pegmatite veins.
Two regions in the state of Baia at present produce emeralds, Vila Nova in the municipality of Conquista, near the Rio Gaviao, and Serra das Eguas in the municipality of Brumado. In these localities they are found in veins of magnesite, constituted of large rhombohedrons of the magnesite itself and of quartz, emerald, tourmaline, topaz, etc. This type of occurrence is very similar to that found in Colombia, the leading producing district of which at present in Chivor.
In the Serra das Eguas there are alluviums with emerald deposits covering an area of 2,000 meters ,by 200 meters. The present operations however are limited to a zone of only 200 meters by 300 meters, partly in the veins, but for the most part in the alluvial deposits. It is possible to prospect these deposits by means of a line of shafts following the maximum declivity. Excellent gems were discovered in this manner at Brumado in the state of Baia.
Ordinary Brazilian emeralds range from 50 milreis to 200 milreis a gram while cut stones vary from 50 milreis to 500 milreis a carat, Eppler however mentions prices up to 10,000 milreis a carat for some stones.
Corundum is an anhydrous aluminum with a hardness of 9, density of 4, and a refraction index of 1.765. It occurs in short bipyramidal prisms. The blue variety is known as sapphire or "engineers' stone" the coloring of which is due to the presence of iron and titanium, while the red stone is the ruby or "lawyers' stone", the coloring of which is attributed to the chromium element ."
http://www.farlang.com/gemstones/jobim-mineral-wealth/page_022
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