Sugilite

• IMA 1974-060
• Sugilite

Sugilite (also Sugilite ) is a rarely occurring mineral from the mineral class of " silicates and Germanates ". It crystallizes in the hexagonal crystal system with the chemical composition KNa2 ( Fe3 , Mn3 , Al) 2Li3 [ Si12O30 ], that is chemically in the idealized form of a potassium - sodium - lithium - iron - silicate. Structurally, it belongs to the ring silicates. The values ​​given in the parentheses of the elements iron, manganese and aluminum can in the formula each represent each other (substitution, Diadochie ), but are always in the same proportions to the other components of the mineral. The superscript and surrounded by square brackets numbers indicate the coordination number for the item.

Sugilite is used exclusively as a gemstone.

Etymology and history

Sugilite was first in 1944 by Professor Ken -ichi Sugi on the small island Iwagi in the Seto Inland Sea, which belongs to the prefecture of Ehime Japan discovered. Analyzed and described the mineral in 1976 by ​​Nobuhide Murakami, Toshio Kato, Yasunori Miúra, Fumitoshi Hirowatari who named it after its discoverer.

Classification

In the now outdated but still in use 8th edition of the mineral classification by Strunz the Sugilite belonged to the department of " ring silicates ( cyclo- silicates) ," where he along with Almarudit, Armenit, Berezanskit, Brannockit, Chayesit, Darapiozit, Dusmatovit, Eifelit, Emeleusit, Faizievit, Poudretteit, Merrihueit, Milarite, Oftedalit, osumilite, osumilite - (Mg), roedderite, Shibkovit, Sogdianit, Trattnerit, Yagiit and Yakovenchukit - (Y) the " Milarite - osumilite group " with the system no. VIII/E.22 formed.

The 9th edition valid since 2001 and of the International Mineralogical Association (IMA ) used the Strunz'schen Mineral classification assigns the Sugilite also included in the department's "Ring silicates ( cyclo- silicates) ." However, this is further divided according to the structure of the rings, so that the mineral according to its construction in the subdivision " [ Si6O18 ] 12 - six- double rings " can be found, where it together with Almarudit, Armenit, Berezanskit, Brannockit, Chayesit, Darapiozit, Dusmatovit, Eifelit, Friedrichbeckeit, Klöchit, Merrihueit, Milarite, Oftedalit, osumilite, osumilite - (Mg), Poudretteit, roedderite, Shibkovit, Sogdianit, Trattnerit and Yagiit forms the unnamed group 9.CM.05.

The mainly common in English-speaking classification of minerals according to Dana assigns the Sugilite in the class of " silicates and Germanates " there, however, in the fine already divided the department " ring silicates: Condensed Rings " field. Here he is in the " Milarite - osumilite group ( Milarite - osumilite subgroup ) " with the system no. 63.02.01a within the subdivision " ring silicates: Condensed, 6 - membered rings " to find.

Education and Locations

Sugilite is hydrothermally formed as part of alkaline syenites aegirinhaltiger. Accompanying minerals ( paragenesis ) can occur in addition to aegirine, you still albite, Allandit, andradite, apatite, Pectolite, quartz, titanite and zircon.

A rare mineral formation Sugilite could be detected only in a few localities, where so far (as of 2013) are about 10 localities known as. Apart from its type locality Iwagi the mineral in Japan only from the Manganerzgrube " Furumiya " on the island of Shikoku is famous.

Known for rich, even crystalline, Sugilithfunde is especially the " Wessels Mine " near Hotazel ​​in the Manganerzfeldern the Kalahari in South Africa.

Other previously known localities include the " Woods Mine" in Tamworth and the " Hoskins Mine" at Grenfell in the Australian state of New South Wales, the " Cerchiara Mine" at Borghetto di Vara (Liguria ) and Castagnola in the community Vagli di Sotto ( Tuscany) in Italy, the quarry " Poudrette " at Mont Saint- Hilaire in Canada, " N'Chwaning mines " in Kuruman and the well " AKH49 " at Sishen in South Africa and the glacier Dara -i - Pioz ( Darai - Pioz ) the Altay Mountains in Tajikistan.

Crystal structure

Sugilite crystallizes hexagonal space group P6/mcc ( Raumgruppen-Nr. 192) with the lattice parameters a = 10.01 Å and c = 14.01 Å and two formula units per unit cell.

Use

Sugilite is sanded depending on the quality and color to match different gemstone shapes and either the board cut as cabochons or offered as a tumbled stone.

High quality Sugilite has glowing purple to reddish color and is always somewhat transparent. Due to the scarcity of current deposits, the host rock is often (gray, brown, red, black, ..) also sold as Sugilite. Good Sugilithe can be recognized by their bright, brilliant color. In the lamplight Sugilithe are strong reddish glow and usually less than in sunlight. When illuminated with white LEDs "light " or the colors shine good Sugilithe particularly intense.

Bad material is easy to recognize. It often shows only little and badly dyed Sugilite shares in the parent rock, which Sugilithanteile especially are more reddish. The "rays" or " lights " the missing colors usually completely or only extremely weak. Some good Sugilithen however, it is often unavoidable that much bedrock is maintained.

Esoteric

In Esoterikerkreisen Sugilite is also known under the trade names Luvulith and Royal Azel and is used either as sidereal pendulum or as an amulet or healing stone with supposedly harmonizing effect on the nerves and brain.