Azul da Bahia

Azul da Bahia
	polished surface of the Azul Bahia
Main features
group	Foyaite
Subgroup	Sodalite foyaite
Occurrence	Brazil, State of Bahia, Itaju do Colônia
colour	blue
use	Floor and wall coverings in buildings, furniture parts, individual craft objects
Dismantling situation	Quarry in operation
Division into hard and soft stone	Hard rock
Age	Proterozoic
Special marks	exclusive natural stone

Azul da Bahia , or Azul Bahia for short , is a plutonite from the rarely occurring Foyaite rock group . This exclusive natural stone has been quarried at Fazenda Hiassu near the small town of Itaju do Colônia in the south of the state of Bahia in Brazil since 1965 . In Germany, this natural stone has been used as decorative stone since the mid-1970s.

Geology and formation

The Azul Bahia formed in the Proterozoic is a sodalite foyaite. It is the largest sodalite deposit in Brazil. In more recent studies, the age of the rock is determined to be 732 ± 8 million years. The rock deposit only extends over a small area of about one square kilometer and is connected to the larger South Bahia Alkaline Province . The Azul Bahia deposit is elliptical and intruded abruptly into a metamorphic rock from the Paleoproterozoic . This resulted in three types of rock, which differ in their strongly differing sodalite content. The deposit areas most in demand for mining have an average sodalite content between 45 and 50 percent.

Azul Bahia is one of the rarely occurring types of blue rock. Foyaites arise from low-silica magmas that contain no quartz and few feldspars .

Rock description and mineral inventory

Azul Bahia is a medium-grained and largely directionlessly textured rock with a blue and white speckled decor. The distribution of minerals can also take on streaky and cloudy shapes and develop veins. The embedded blue sodalite crystals give the color. The whitish feldspars brighten the rock and also form white veins in the rock. The stored biotite can be seen in the form of black crystal aggregates. Biotite crystals can also occur partially (see stone pattern).

Azul Bahia is composed of microcline , plagioclase , sodalite, nepheline and cancrinite , aegirine and / or epidote and biotite. Furthermore occur pyroxene on, ores and other rare minerals.

use

Blue rocks are rare and have a spectacular appearance, which is why Azul Bahia is mainly used for exclusive applications. All blue colored foyaites are very expensive due to their rarity. This sodalite stone is used either as a natural stone or as a gem stone.

Azul Bahia is mainly used for floor and wall coverings inside buildings. The sodalite foyaites react to the use of acids , alkalis , hot water and permanent moisture (especially the mineral sodalite, which colors the foyaite blue). An installation of these rocks can only take place after expert advice and with knowledge of the risk of discoloration.

Azul Bahia is a hard stone , is frost-resistant and can be polished.

Usage examples

Vienna , Stephansplatz 9: former Ellert shop facade (facade design: architect Robert Kaiser , 1980)
Berlin , Panoramastraße 1: interior design of Café P1
Nuremberg , Kaiserstraße 10: shop facade (architect H. Schmidt, around 1990)
Speyer , Verbum Scroll Fountain, the manet in aeternum in front of the Memorial Church , art object of the Kubach-Wilmsen couple

Web links

Application examples of Azul Bahia for interior design and furniture design

Individual evidence

↑ Eraldo Bulhões Cabral: Química Mineral do Stock Foidolítico Itaju do Colônia, Sul da Bahia. 2008 (Portuguese, Pdf Online , accessed September 13, 2014).
↑ Raymond Perrier: Les Roches Ornementales . Ternay (edition pro roc) 2004, p. 252 ISBN 2-9508992-6-9
^ Friedrich Müller: INSK compact. The international natural stone index for the current market . Sheet 32.4. Azul da Bahia . Ebner Verlag, Ulm 1977.
↑ Robert sailor and Herbert Summesberger: Wiener stone walking paths, the geology of the big city . Brandstätter, 1999, ISBN 3-85447-787-2 , p. 88
↑ Johannes H. Schroeder (Ed.): Natural stone in architecture and building history of Berlin. A stroll through the town between Alexanderplatz and the Großem Stern . (Guide to the geology of Berlin and Brandenburg; Vol. 6). 2nd edition. Self-published Geoscientists in Berlin and Brandenburg eV, Berlin 2006, ISBN 978-3-928651-12-7 . P. 241
↑ Johannes H. Schroeder (Ed.): Stones in German cities . Self-published Geoscientists in Berlin and Brandenburg eV, Berlin 2009, ISBN 978-3-928651-13-4 . P. 224
↑ Illustration on www.panoramio.com

[1] Eraldo Bulhões Cabral: Química Mineral do Stock Foidolítico Itaju do Colônia, Sul da Bahia. 2008 (Portuguese, Pdf Online , accessed September 13, 2014).

[2] Raymond Perrier: Les Roches Ornementales . Ternay (edition pro roc) 2004, p. 252 ISBN 2-9508992-6-9

[3] Friedrich Müller: INSK compact. The international natural stone index for the current market . Sheet 32.4. Azul da Bahia . Ebner Verlag, Ulm 1977.

[4] Robert sailor and Herbert Summesberger: Wiener stone walking paths, the geology of the big city . Brandstätter, 1999, ISBN 3-85447-787-2 , p. 88

[5] Johannes H. Schroeder (Ed.): Natural stone in architecture and building history of Berlin. A stroll through the town between Alexanderplatz and the Großem Stern . (Guide to the geology of Berlin and Brandenburg; Vol. 6). 2nd edition. Self-published Geoscientists in Berlin and Brandenburg eV, Berlin 2006, ISBN 978-3-928651-12-7 . P. 241

[6] Johannes H. Schroeder (Ed.): Stones in German cities . Self-published Geoscientists in Berlin and Brandenburg eV, Berlin 2009, ISBN 978-3-928651-13-4 . P. 224

[7] Illustration on www.panoramio.com