Palissandro Bluette

Building design
ranging from shades of brown to shades of blue

Petrology, also known asthe study of rocks, is the science of the formation, properties, and uses ofrocks. In our online series, we introduce different types of stone and their occurrences: This time, Palissandro Bluette.

Palissandro is available on the market in various color varieties, ranging from brown to blue tones. Photo: Abraxas stone experts/Giesen

Palissandro Bluette is a dolomitic marble. Compared to calcitic marbles, which consist primarily of the mineral calcite—such as Carrara marble—dolomitic marbles exhibit greater resistance to chemical and mechanical stress. Dolomite marbles consist primarily of the minerals dolomite and calcite. However, dolomite marbles may also contain other minerals that contribute to their decorative appearance.

In the case of Palissandro Bluette, this is the phyllosilicate (layered silicate) phlogopite. This mineral belongs to the group of mica minerals and formed during the metamorphic transformation of the rock. In Palissandro Bluette, it occurs in small flakes, most of which are no larger than one millimeter. In the field of natural stone, phlogopite is relatively rare as a decorative mineral. Nevertheless, it is found throughout the Earth’s crust worldwide. These layered silicates can also vary greatly in size. For example, a phlogopite five meters in diameter was discovered in the Irkutsk region of Siberia.

Read more in the upcoming issue of STEIN 1/2021, which will be published on December 21, 2020.

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Light and shadow in Cologne

Building design

L.-Fritz-Gruber-Platz is only about 400 meters away from Cologne Cathedral as the crow flies. For its design, the Düsseldorf-based firm scape Landschaftsarchitekten took up the theme of photography. The result is a play of light and shadow.

L. Fritz Gruber Square is located just 400 meters from Cologne Cathedral as the crow flies, right next to the Kolumba Art Museum of the Archdiocese of Cologne, which was built in 2007 according to plans by Peter Zumthor. The square is named after the photographic historian and journalist Leo Fritz Gruber. From 1945, he worked as a photographer for the British Army of the Rhine. This passion never left him. The Düsseldorf-based firm scape Landschaftsarchitekten therefore took up the theme of photography for the design of the square. A play of light and shadow creates a two-dimensional image of the large maple trees on the square. The square is bordered by listed facades from the 1920s and 1960s. Typical local basalt cobblestones surround a rectangular area of light-colored concrete slabs with an aspect ratio of 6:9 (small picture format), which is framed by three white cuboid benches.

Shadow plays are created on this projection surface, which is illuminated at night by a luminaire hanging above the square in the shape of a hollow sphere. Objects that cross its beam of light create sharply defined shadows on the paving. The functional principle is similar to that of a projector: a hollow body with a matt black inner surface and a point-shaped light source, the opening of which is dimensioned at the bottom so that the focal point beams precisely trace the surface of the square.

L.-Fritz-Gruber-Platz, Cologne

Client: City of Cologne – Civil Engineering Department
Open space: scape Landschaftsarchitekten, Düsseldorf
Project management: Hiltrud M. Lintel, Rainer Sachse
Collaboration: Jan Heimann, Judith Pfahler, Markus Hilgers, Bernd Nengel
Competition: 2007, 1st prize
Completion: September 2012
Area: 2,200 square meters
Costs: 570,000 euros

A stroke of art-historical luck

Building design

The Gothic sacristies of the parish church of St. Quirinus in Tegernsee are to be restored. Many eras have left their mark on St. Quirinus, which was the monastery church of the most important Benedictine abbey in Upper Bavaria until 1803.

The Gothic sacristies of the parish church of St. Quirinus in Tegernsee are to be restored. Many eras have left their mark on St. Quirinus, which was the monastery church of the most important Benedictine abbey in Upper Bavaria until 1803.

The sacristy used today dates from the Baroque period, but the two Gothic sacristies with their vaults and rare gray-on-gray painting are a stroke of art-historical luck. These are now used as storerooms, albeit for valuable items from the monastery or handicraft objects such as candlesticks or figurines.

The approval of the preliminary investigation for the restoration means that the sacristies will now be cleared out so that they can be made accessible to the public at some point in the future. Church historian Roland Götz has taken a closer look at the sacristies and knows that their preservation is a stroke of luck. However, fire protection still needs to be clarified, as there are no escape routes. As the church is under the same roof as the Bräustüberl, the castle distillery, the grammar school and the brewery, all those responsible and the owners must first come to an agreement. How much all the measures would cost is now to be found out in advance.