Sepiolite

• Meerschaum

Mineral sepiolite, commonly known as sepiolite, is rarely occurring magnesium silicate having the chemical composition MG8 [( OH) 2 | Si6O15 ] 2 x (4 8) H2O. According to its crystal structure, it is one of the phyllosilicates. It crystallizes in the orthorhombic crystal system and has only been found in the form of earthy or massive, bulbous rarely fibrillar mineral aggregates of white, off-white or yellowish-white color.

Not to be confused with the mineral, the plant is sea moss, which is also known as sea foam.

Special Features

Sepiolite has theoretically, based on the possible packing density of the unit cell, a density of 2.26 g / cm ³. However, the mineral is often porous, that is similar to pumice contains a lot of air, which can reduce its density to such an extent that it will float.

Before drying, the meerschaum tuber is growing soft and oily to the touch. By contact with water, it foams like soap and has therefore already been used by the Greeks for cleaning purposes. For pipe production, this tuber is excellent, as they are easy to work with and because of the porous structure is very absorbent. The mouthpiece is however made ​​from other materials because the tongue would stick to sepiolite.

Etymology and history

The origin of the name meerschaum is explained differently. One interpretation is based on the Levantine trade name mertscavon. The Austrian traders who at the time controlled the sea foam market would have the unspeakable word Germanized so. A connection with " foam " is certainly obvious to the whitish, sometimes yellowish or light gray tinted while porous mineral.

Duden gives as origin a loan translation of Latin spuma ( Marist ), original a name for corals.

Author of the scientific name sepiolite ( to Greek sepion " squid " ) is Ernst Friedrich Glocker, of being able to establish said in 1847 that sea foam is formed from deposits of fossil shells and fish cartilage. Also on the similarity with the white porous mass of Sepia Schulps remembers the name.

As a type locality applies the old magnesite quarry " Bettolino " in the Italian community Baldissero Canavese ( Piedmontese Bausser ).

Classification

In the now outdated nomenclature of minerals by Strunz ( 8th edition ) of the sepiolite to the general ward of a part " layer silicates ( phyllosilicates ) ". The revision of the Strunz'schen Mineral classification in the 9th edition also this department was precisely divided according to the structure of the compound and the mineral is now in accordance with the subdivision of a "Simple tetrahedral nets of six-fold rings, connected by octahedral nets or straps ".

The commonly used in English-speaking classification of minerals according to Dana assigns the sepiolite in the department of " layer silicates: modulated layers with connected strip " and there along with Falcondoite and Loughlinit in the " palygorskite Sepiolithgruppe ( sepiolite - subgroup ) ."

Education and Locations

Sepiolite is hydrothermally formed by conversion of serpentinite. Accompanying minerals include dolomite, Loughlinit, magnesite, montmorillonite, opal, palygorskite and serpentinite.

As a rather rare mineral sepiolite formation can indeed be abundant in part to different sites, overall it is not very common. So far (as of 2013) are considered to be known around 200 localities. Apart from its type locality " Bettolino " entered the mineral in Italy or other places in the region Canavese (Piedmont), in the " Monteneve Mine" (Snow Mountain Mine) in the Passeiertal (Trentino -Alto Adige), at Serrazzano in the community Pomarance (Tuscany) and at some points Fund in the province of Vicenza (Veneto ) on.

The classic localities, however, is one of Turkey, specifically the province of Eskişehir with its tertiary clay deposits. Another well-known deposit of sepiolite is located in Tanzania. This is known as " Amboseli Meerschaum " and a few million years younger than his Turkish relatives. " Amboseli Meerschaum " is heavier, usually coarser textured and has a gray tint.

In Germany the mineral previously occurred on Peterleinstein at Kupferberg and in the quarries " Hess " in Wurlitz ( Rehau ) and " Haidberg " in cell in Bavaria, on the Rother head near Gerolstein in the Rhineland-Palatinate Eifel and at Schneeberg in Saxony's Erzgebirge.

In Austria sepiolite could, among other things at the hut Erzberg and the Millstätter Alpe in Carinthia, are found on the skull in the Salzburg Hohe Tauern mountains and at several places in Lower Austria and Styria.

The only known locality in Switzerland Ronco Bedretto in the canton of Ticino.

Other localities lie including Australia, Brazil, China, Dominican Republic, France, Greece, Greenland, Indonesia, Israel, Japan, Canada, Kenya, Colombia, Madagascar, Malaysia, Mexico, Morocco, Norway, Poland, Romania, Russia, Sweden, Slovakia, Spain, South Korea, Czech Republic, Hungary, Venezuela, the United Kingdom ( UK) and the United States of America (USA).

Crystal structure

Sepiolite crystallizes in the orthorhombic space group Pncn ( Raumgruppen-Nr. 52) with the lattice parameters a = 13.405 Å; b = 27.016 Å and c = 5.2750 Å and four formula units per unit cell.

Use

Sepiolite is mined primarily for the manufacture of meerschaum pipes. It also serves for the production of jewelry, such as bracelets, necklaces and others.

Previously, Vienna was the capital of meerschaum pipes production, well-known manufacturers are Andreas Bauer, Leopold Weiss and Strambach.

The economic conditions of Turkey have led to sea foam must not be exported as raw material. It must be processed in Turkish workshops to whistle or jewelry. Only so-called semi-finished products are allowed to leave the country to be fitted and polished in other countries with a mouthpiece.

From ground meerschaum (mostly from defective production or residues), lime and cement Press Meerschaum Pipes (Massa -Meerschaum or Vienna Meerschaum called ) are produced. Small sea foam pieces are used instead of the more common activated carbon for the production of pipe filters. Due to its porous structure, also it takes fluids on very well and is therefore used as a cat litter. As a further application of the so-called sea foam dust is considered the removal of fat stains in the household.