Stukenberg Geology Museum of Kazan State University
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Silicates

The class of silicates is the biggest class of minerals. These minerals are compounds of silicooxigenous acid anion radicals with the following basic ions: Al, Fe, Mg, Mn, Ca, Na, K, as well as those of the group (OH), F, S, Cl, (BO3), (SO4) and others.


Traditionally this big class is divided into several subclasses, groups and subgroups in particular nesosilicates, cyclosilicates, inosilicates, phyllocilicates and tectosilicates in accordance with their crystal structure.


Silicates are widely spread in the earth shell and total 75% of it. Many of these minerals are rock-making and form the body of different rocks, i.e. silicates are the main building material of the lithosphere. They are the most important useful minerals, used by man since ancient times. They find an application as bonded refractory, ceramic raw materials, electrical and thermo-isolation. Some of silicates are ores of Be, Li, Zn, Ni, Zr, Tr, and there are a lot precious and industrial stones among them.


A systematic collection of Mineralogy Section of the KSU Geology Museum represent all the subdivisions of silicate class. As for nesosilicates there are nice zircon, chosen from pegmatitic vein of the Ilmen State Reserve at different times, crystals of phenacite from the Urals emerald mines, and topaz crystals from the unique Volyn deposit (Ukraine).


Mineralogy of metamorphic complexes of the Urals is introduced by radial aggregates of light-blue cyanite, columnar crystals of rose andalusite and cruciform twins of brown staurolite crystals.


The group of exhibited wonderful gem-stones, garnets, is represented by all their main types such as red pyropes, crimson almandines, honey-yellow spessartines and grossulars, brown andradites and green uvarovites. There are also rare garnets in the collection: black melanites from the Yenisei ridge and green demantoids garnets alluviated in placers of Nizhniy Taghil region of the Urals.


Crystals and aggregates of epidote are characterized by wonderful decorative properties. A big number of epidote samples demonstrate a black type of the mineral, namely, pushkinite.


Cyclosilicates unlike all the others is characterized by a great variety of gem-stones. The Mineralogy Section shows the main jeweler types of beryl (emerald, aquamarines, heliodor, vorobyevite, most of them have been extracted in the Emerald mines and in Adun-Cholon Deposit (Baikal Region).

 
Topaz on Quartz, the Urals
Topaz on Quartz,
the Urals



Garnet (Andradite). The Yenisei Mountain Ridge
Garnet (Andradite).
The Yenisei Mountain Ridge



Beryl. Adun-Cholon. Baikal Region
Beryl.
Adun-Cholon. Baikal Region
 
 


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