Pectolite
The mineral Pectolite, occasionally Pectolit (h ) or Pecktolit written or known under the synonymous name Gonsogolit, Schizolite, Stellite and Alaska Jade, is a chain silicate from the wollastonite group, which may be abundant in various localities in part, a total of but little is common.
Crystallizes in the triclinic crystal system Pectolite with the chemical composition Ca2Na [ Si3O8OH ] and often developed fibrous to columnar crystals in parallel or radialstrahliger arrangement.
It is known mainly used as a gemstone, blue clouded over white variety Larimar.
Special Features
Reiner Pectolite is colorless and transparent. But it may also appear white and accept by foreign admixtures, a gray-white, yellow, pink or rarely blue-green tint by multiple refraction due to lattice defects or polycrystalline training, the transparency decreases according to the opacity. Visible crystal faces have a glass-like shine on, acicular and fibrous aggregates, however, rather pearl or semi-gloss.
In its properties Pectolite is very similar to the wollastonite and the Bustamite.
Etymology and history
Pectolite was first found pektos at the designated as " Sano " slopes of Monte Baldo near the town of Mori in the Italian province of Trento ( Trentino Alto Adige ) and described in 1828 by Franz von Hess Peter, the πηκτός the mineral by the Ancient Greek words for " curdled " or " originated from different parts " and lithos for stone λίθος named.
Classification
In the now outdated but still in use 8th edition of the mineral classification by Strunz the Pectolite belonged to the mineral class of " silicates and Germanates " and then to the Department of " chain silicates and phyllosilicates ( inosilicates ) " where he, along with Bustamite, Cascandit, Denisovite Ferrobustamit, Foshagite, Jennit, Serandit, Vistepit and wollastonite formed a distinct group.
The valid since 2001 and used by the IMA 9th edition of the Strunz'schen Mineral classification assigns the Pectolite also in the class of " silicates and Germanates " department " chain and chain silicates " one. This division, however, is further divided according to the structure of the chain formation, so that the mineral is " with 3- periodic single and multiple chains chains and chain silicates " to find according to its construction in the subdivision where it, along with Bustamite, Cascandit, Ferrobustamit Serandit, Tanohatait and wollastonite forms the unnamed group 9.DG.05.
The classification of minerals according to Dana assigns the Pectolite in the class of " silicates and Germanates " and there in the department of " chain silicate minerals ." here he is with the eponymous wollastonite and the other members Bustamite, Ferrobustamit, Serundit, Cascundit and Denisovite the " Wollastonitgruppe " with the system no. 65.02.01 within the subdivision " chain silicates: Simple unbranched chains, W = 1 with chains P = 3" forms.
Modifications and varieties
Larimar is a blue-white clouded over variety of Pectolite that far (as of 2010) could be detected only at two localities: In a converted, ultrabasic volcanic rock on the Barahona Peninsula in the Dominican Republic and the " Fitta " in Soave in Italy. Larimar has nothing to do with the also occurring on Hispaniola blue amber, which is sometimes processed in the same factories in Puerto Plata and in the same way as Pectolite.
Larimar was only discovered in 1974 ( that of Larimar is said to be already known to the natives of the island, is a legend ) and is used commercially since the early 1980s as a gemstone. Over white Pectolite of Larimar is harder (up to 6 on the Mohs scale ) and only occurs in dense, finely crystalline aggregates. The sky blue color ( not copper, as it is evidence of Cu-free Larimare ) is due to trace amounts of vanadium; next greenish varieties occur, the color is probably only due to lattice defects.
Education and Locations
Pectolite either forms primarily in nepheline syenites or hydrothermally in columns, fissures or Druze basaltic igneous rocks. It often occurs in paragenesis with various zeolites, Datolith and prehnite.
Overall Pectolite has so far (as of 2011 ) can be detected at around 300 localities. Apart from its type locality Monte Baldo, the mineral in Italy nor in several places in the Valle d'Aosta, Liguria, Piedmont, Trentino -Alto Adige and Veneto was and in Malencotal (Val Malenco ) in the Province of Sondrio ( Lombardy ) and in the municipality of Castelnuovo di Val di Cecina ( Tuscany) found.
In Germany Pectolite occurred in Baden-Württemberg, among others, in the Black Forest and the Emperor chair; Glad at Bach and Steinperf in Hesse; in the Sauerland region in North Rhine- Westphalia as well as in low- churches, Bisterschied and Wolf, in the Rhineland -Palatinate.
Noteworthy due to exceptional Pektolithfunde among other West Paterson in Passaic County (New Jersey) in the United States of America ( USA), where needle-like and spherical aggregates of up to 18 cm in diameter were revealed. Up to 5 cm long, prismatic crystals were recovered in the Canadian province of Quebec at Mont Saint- Hilaire.
Other localities include Australia, Brazil, China, Denmark, the Dominican Republic, Finland, France, Greece, Greenland, Ireland, Japan, Canada, Madagascar, Mexico, Morocco, New Zealand, Norway, Poland, Russia, Sweden, South Africa, Tajikistan, Czech Republic, the United Kingdom ( UK ) and other places in the aforementioned countries, Canada and USA.
Crystal structure
Pectolite crystallizes in the triclinic space group P1 ( Raumgruppen-Nr. 2) with the lattice parameters a = 7.98 Å; b = 7.02 Å; c = 7.02 Å; α = 90.5 °; β = 95.1 ° and γ = 102.5 ° and two formula units per unit cell.
Use
The Pectolite itself has no direct economic importance. His variety Larimar is, however, due to its blue - white, cloudy appearance quite a popular gemstone whose colors match best comes cabochon-cut advantage.