- Zustand: unused FDC´s
- Jahr: 2018-10-12
Euchroite Cu2(AsO4)(OH)•3H2O is among the most beautiful Slovak secondary minerals. Its name was derived from the Greek word euchros, meaning beautifully coloured. Euchroite was first described in 1823 by J. F. August Breithaupt (1791 – 1873), a professor of mineralogy at the Freiberg Mining Academy, however, this came from the world-renowned deposit at Svätodušná.
Euchroite is a supergene mineral that crystallises as an orthorhombic crystal. It is copper arsenate that forms isometric, tabular, short-prism crystals of mostly emerald green or, less frequently, a blue-green colour. It is normally transparent with a glassy gloss; however, typically some crystals, such as isomeric crystals, have a matt gloss. In Ľubietová, it forms in crystals of more than 1cm long, sometimes forming beautiful aggregates several centimetres in length along the cracks of metamorphosed rocks. Most of the time, it is found with olivenite, strashimirite, malachite and parnauite.
Ľubietová-Svätodušná still holds the world's most significant deposits of this mineral, with the most beautiful and largest crystals and aggregates of the mineral being housed in all of the world's leading museums. Other important deposits of Euchroite include those at Poniky-Farbište in Slovakia and Zapačica in Bulgaria.
The maximum card (CM) bears the image of typical crystals of Euchroite from Ľubierová, rising from black flowing aggregates of Fe-Mn oxides. Part of the crystals on the maximum card is also depicted on the stamp; another double crystal of Euchroite is the theme of the FDC surcharge. On the postage stamp introducing the issue, there is the typical crystal shape of Euchroite from Ľubierová, which was published in 1957 by the important Austro-Hungarian mineralogist, crystallographer and physicist, Wilhelm Josef Grailich (born in Bratislava in 1829) and the leading Austrian chemist, Viktor von Lang (1838 – 1921).
Among foreign mineralogists and collectors, Libethenite Cu2(PO4)(OH) is probably the best known mineral from Slovakia. It was first described in 1823 by J. F. August Breithaupt, a leading mineralogist of the 19th century, a German professor at the Freiberg Mining Academy. He named it after the German name for the town of Ľubietová – Libethen. The importance of this mineral has also been underlined by the fact that the crystal is the central theme of the logo of the Mineralogical Society of Slovakia – today's successor to the world's second oldest mineralogical society, founded in 1811 in Banská Štiavnica.
Libethenite crystallizes in an orthorhombic crystal system and mostly forms short-prism or dipyramidal emerald green to green-black crystals. Crystals of up to 11 mm in size are mainly found with malachite and pseudomalachite in the oxidation zone of the deposit at Podlipa near Ľubietová, which is still the world's most significant deposit of this mineral. Other important locations include e.g. Portugal, England, Russia, Zambia, etc.
The stamp and maximum card (CM) bear the image of a typical dark-green Libethenite crystal from the Dolná Ladislav shaft in Ľubietová. On the first day cover (FDC), there is a typical sample of corroded quartz with Libethenite crystals from Ľubietová on the surcharge. On the postmark with the date of the first day of the stamp issue, there is the typical shape of the crystals of Libethenite from Ľubietová, which was originally published by the important Hungarian mineralogist and crystallographer, Gustáv Melczer, in 1904 (born in 1869 in Dobšiná). In the interstitial, there is a depiction of a flowing aggregate of malachite from Ľubietová, the Podlipa deposit. This mineral is the most abundant mineral in the oxidation zones of copper deposits and it may also be found in abundance in both deposits in Ľubietová.
Meer tonen
Ontdek de verzamelaarsagenda!
Ontdek de agenda
