The entrance to the Mineralogical and Petrological Exposition, which is among the most significant of European collections, is from the Pantheon on the left of the main entrance. Often they are unique scientific exhibits, placed in the original showcases dating from the time of the construction of the Museum. These showcases were an entirely unique phenomenon itself in their time, because they were – and partially still are – absolutely dustproof.
In the first hall, we find minerals from the whole world arranged according to the mineralogical system – from elements to complex silicates. The visitor’s attention will be drawn to the samples of pure copper, gold, silver, natural diamonds, but also to the very precious exhibits of silver sulphides – Pyrargyrite and Proustite -- protected by dark boards against the influence of light. In the cubic showcases we can see particularly large and crystallised samples of minerals, for example rock-salt, violet types of flint – Amethyst, hair-like Millerite and others. The original collection of grinded gemstones and the showcase with glass imitations of the world’s most famous diamonds are on display at the end of the hall.
A world-significant collection of meteorites and tektites, moldavites and systematic collection of rocks is located in the right corner hall. There are also two significant columns from Panská skála near Kamenický Šenov and the models of large iron meteorites that were found on our territory (Loket, Broumov). The adjoining small hall contains a modern exposition of gemstones. There are both grinded and natural crystallised minerals on display. We find diamonds there, the hardest and the most popular gemstones, both separate and buried in the maternal mineral, Kimberlite. In particular, two uniquely yellowish diamonds deserve special attention. Together with diamonds, also the coloured Corund varieties – fire-red Ruby and blue Sapphire – are among the most remarkable treasures. The coloured varieties of Topaz also deserve our admiration; the weight of the biggest blue Topaz is 1,463 carats. The gemstone varieties of Beryl – Aquamarine and especially Emerald – are very precious. Two green Brazilian Beryls and a cluster of crystals of pink Morganite are unique in the world. Pink Kunzites, varicoloured Tourmalines, Fluorites, Hematite and Sphalerite are also worthy of interest. Gemstones characteristic of our territory include fire-red Garnets, green Olivines and the coloured palette of various flint varieties, from pure rock-crystals through to Morions, Amethysts and Citrines to Agates and precious Opals.
The next two halls are devoted to Czech minerals. The first hall displays the samples of rich and, today already historic, ore deposits. Our world-renowned ore deposits - Kutná Hora, Jáchymov, Příbram – are represented by rich exhibits of both ore minerals and accompanying minerals, rocks and venous textures. We also find here the largest exhibit of a Czech gold nugget, weighing 16.5 grams, found accidentally in Křepice u Vodňan (South Bohemia) in 1927.
In the last hall of the mineralogical exposition we find the samples of Czech non-ore minerals arranged according to the geological age of the mineral environment. The best known location of Czech gemstone findings is in the region below the Giant Mountains – beautiful samples of Agate and Jasper – and the Czech Central Mountains where the sediment loads contain in particular the fire-red Czech Garnets – Pyropes. This is also where the first Czech diamond was found (Dlažkovice).
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