Showing 3 results for Agate
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Volume 19, Issue 3 (10-2011)
Abstract
Agate mineralization in the Mianeh area is occurred in the open space filling form in the Eocene volcanic acidic rocks. High potassic and shoshonitic nature of the volcanic rocks have been related to active continental margin setting. The host rocks of the agates are mainly ignimbrite and rhyolite. Blue, red, orange, grey, green and black colors, stelled, cauliflower, fibrous, radiated, circular structures and banded and fibrous textures are seen in the agates. The most important factor causing blue color is copper and for black, red and smoky colors are iron and manganese. Samples have good polishibility and transparency, hardness is 6.7-7 and density is 2.64. Fluorescence and pleochroism features are lacking. The aluminum and volatile amounts show decreasing versus increasing of the silica in the agates. The behavior of REE shows a similar magmatic nature for the studied agates. Practical experiences showed that the best temperature for artificial dyeing for red and orange colors is 500 ºC and for light-dark blue is 550 ºC.
Elnaz Jami Al Ahmadi, Iraj Rasa, Fariborz Masoudi, Niloofar Mousavi Pak,
Volume 27, Issue 1 (4-2019)
Abstract
Opal, known as Aghigh in Persian, is one of the main semi-precious rock in Iran that is present in Bayag active mine in NW of Torbat Heidarieh. Mineralogy of agate is crucial for its treatment and cutting. In this research, mineralogy of agate in Bayeg mine investigated using SEM, Raman analyses and ICP methods. Chalcedony introduced as the main constituent of agate in literature. However, this research revels opal, chalcedony and moganite are main minerals of Bayeg mine respectively. In hand specimen, chalcedony show white and milky color, and opals are gray to dark. ICP-MS analysis showed that amounts of AL and Na, Ba and Sr present as trace of meteoric and hydrothermal fluids and igneous activities during the formation of opals
Maryam Shakooei, Arezoo Abedi, Seyed Reza Mirbagheri,
Volume 28, Issue 2 (6-2020)
Abstract
The Chah Andoo plain is located about 100 km SW Damqan in Semnan Province. Basalt, andesite-basalt, tuff and metamorphic rocks are the main rocks which exposed in the study area. Agate, jasper and agate–jasper are silica minerals widespread at the plain surface as crushed fragments from a few millimeters to 0.5 meter in dimension. Banded (mono centric), stalactite (landscape), mossy and thunder egg agates are the most frequent agate types in the area. Jaspers can be observed as banded, mossy, massive and different color types. Low quartz and moganite as the main silica polymorph minerals with impurities such as hematite, carbonate, chlorite and carbonaceous organic material were determined by micro Raman spectroscopy. Moganite is identified in the silica mineralization for the first time in the study area.
