Marienglashohle Friedrichroda – Crystal Cave
Crystal Grotto Where Calcite was Mined to Decorate Religious Objects
Jul 27, 2008
The Marienglas cave is a couple of km away from the pretty spa town of Friedrichroda in the Thuringer Forest region of Germany.
Marienglas is clear calcite crystal, found in this region where gypsum was mined. It was prized by churches and abbeys, because it gives a beautiful translucent effect which makes good use of candlelight in chandeliers and candelabras. Large crystals could be split along the crystal planes to form transparent panes, which were of a better optical quality than much contemporary glass at the time. This was used to ‘glaze’ picture frames.
Tour
Access to the caves is only via the guided tour, which is in German. Visitors are taken along the 110m access shaft which shows some of the steeply sloped layers of different rocks. Once inside the mines, the first exhibit is the large work room, where the small stature of the miners can be seen in the height of the exploratory shaft. Mining was heavy work in poor conditions and miners rarely saw the other side of their fiftieth birthday due to the physical toll of the hard work and damp atmosphere. This work cave is ‘graced’ by an ugly artificial waterfall using water pumped up from lower levels – this was installed in 1968 by the Communist government which clearly lacked taste in its tourist attractions. However, from this point on the tour soom coves to the star attraction, which is the fine crystalline deposits in the Marienglas cave itself. Fortunately mining was prohibited in time to preserve some of the beauty. Another slightly cheesy 1970s effect is when the tour reaches the caves, the lights are dimmed and the theme tune from Close Encounters of the Third Kind is played as they are faded up to reveal the beauty of the grotto. This time the effect works reasonably well. At the end of the tour a piece of Marienglas and a piece of amorphous calcite which is chemically the same thing are passed round the group to everybody can get a closer look.
There are no particularly tightly enclosed places, and visitors of normal height do not need to stoop other than to avoid some low lintels – there are no long low tunnels.
History
As far back as 1538 iron ore was mined in the hillside, and this was the main activity at the site for a long time. In 1778 miners made test drillings to see if the rock held other useful materials, such as copper ores, but found only gypsum. A few years later, in 1784, they came across the crystal grotto, which was originally a void in the rock. In this the calcium sulphate crystallised out of solution, almost filling the void. Mining of the calcite continued to 1848.
The mine was difficult to work because air was only supplied along the narrow entrance passage - only about four miners were able to work at any one time using dim lamps fuelled by vegetable oil.
How To Get There
From the Bundesautobahn 8 take the exit to Waltershausen, and follow the B88 to Friedrichroda. The car park is signposted from the B88 about 1km from Friedrichroda in the direction of Eisenach.
By public transport take the Thuringer Waldbahn (tram) from Friedrichroda. The town is on the German rail network. For a slower but more picturesque alternative take a horse and cart leaving from the town centre.
Location
Marienglashohle on Google Maps
GPS Location
50.86375 N 10.54191 E
 |
 |
 |
 |
 |
