Chalcedony

chalcedon 1 z knihy

Width of the photo: 58 mm, Slovakia. Source: Drahé kameny, Jiří Zimák, Vydavatelství Univerzity Palackého v Olomouci, 2008

Belonging among general gemstones, chalcedony is the translucent variety of quartz. Often we can see it in different shades of white, grey, blue-grey, green- grey and shades of yellow to brown even to red. His other varieties are for example carnelian, chrysoprase, onyx, agate or jasper. Deposits are all over the world; in India, Canada, the USA, Mexico, Brazil, Australia and New Zealand, partly in Europe, etc.; Czech deposits are not very significant, although there are several. Its name probably comes from town of Chalcedon (Chalkedon) in Asia Minor (now it is part of Istanbul).

Chalcedon_2-Minerál chalcedon ze sbírek Národního muzea původem z Nové Paky WIKI

Chalcedony from collections of National Museum od the Czech Republic, originally from town Nová Paka. Source: http://cs.wikipedia.org/wiki/Chalcedon#mediaviewer/File:Chalcedon_2.jpg

In his work Historia Naturalis, Pliny the Elder mentions it as variety of jasper; chalcedony is also mentioned in the Bible. Chalcedony was found among treasures of deposit Tillya Tepe in Afghanistan (there were extremely rich burial mounds from around the 1st century BC). In the Mediterranean, there is evidence of its use since the Bronze Age; eg. from around 1800 BC, chalcedony seals findings come from palace at Knossos (Minoan culture of Crete). On the territory of the Czech Republic, chalcedony is historically mentioned in connection with carving workshop of Miseroni family (from 16th century); chalcedony was used for example as a material for cameos (the most famous ones being  with portrait of Rudolf II.). For centuries it is attributed to a range of protective and healing functions.

chalcedon Řím

Photo of a cameo with the head of Titus on it from the 2nd century AD made from Chalcedony. Museo Archeologico Nazionale, Florence. Photo taken by Steve Karg. Source: http://en.wikipedia.org/wiki/File:Titus_cameo.jpg

chalcedon NPS

Chaco Anasazi, Site number, Bc 51, AD 1000-1200 Chalcedony. L 10.8, W 2.5, T 0.7 cm. Chaco Culture National Historical Park, New Mexico, USA. Source: http://www.nps.gov/museum/exhibits/chcu/obj/fullres/knife_chcu1279_full.html

chalcedony wulflund

Chalcedony earrings. Source: http://wulflund.com/jewelry/fantasy-jewels/chalcedony—earrings.html/

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