Painite
Painite is a very rare mineral from the mineral class of " borates " (formerly " carbonates, nitrates and borates ", see Classification ). It crystallizes in the hexagonal crystal system with the chemical composition CaZrAl9 [ O15 | BO3 ], and developed hexagonal prismatic to acicular crystals in red, orange, red or brownish in color. Coloring foreign admixtures are chromium, vanadium and iron.
Special Features
The colors of the Painitkristalle range from brown ( sometimes greenish strongly ) on reddish-brown to red (in all luminosities from clear to almost black). Some pieces are light purple to pink. Some pieces, especially the radiating aggregates, show distinct zonation. Painite is strongly dichroic. About Twins Painite has so far not been clearly published, even if quite a few pieces have been observed with regular adhesions, including a specimen with perpendicular intergrown crystals. Here it is, however, yet to be seen whether there are actually twins.
Part of the Painite (share previously unknown) has a color change from brown to red-brown in the sunlight on the light bulbs. This very well recognizable color change has been previously classified by the so far only examined job as too small to be recognized. However, this is understandable, as these pieces ( Limoniteinschlüsse are disturbing, clear pieces are necessary for observation) a clear weak greenish brown and in lamplight show a clear pink with no brown spots in daylight ( sun). The color change is perfect and easy to recognize.
Etymology and history
Was first discovered in Painite Ohngaing, near the town of Mogok in Mandalay Division of Myanmar (formerly Burma) and described in 1957 by Claringbull, Hey and Payne that the minerals by Arthur Charles Davy Pain ( -1971 ), a British mineralogist and gemologist.
Classification
In the now outdated but still in use 8th edition of the mineral classification by Strunz the Painite belonged to common mineral class of " carbonates, nitrates and borates " and then to the Department of " island borates ," where he along with Fluoborit, Jeremejewit and Karlit an independent group formed.
The 9th edition valid since 2001 and of the International Mineralogical Association (IMA ) used the Strunz'schen Mineral classification assigns the Painite in the new class of " borates " and there in the department of "Mono borates " one. This division, however, is further subdivided by the structure of the borate complex, and the possible presence of other anions, so that the mineral according to its composition in the subsection " BO3 with additional anions; 1 (D) OH etc. can be found "where it forms the unnamed group 6.AB.85 the only member.
In contrast to the predominantly Strunz'schen systematics common in English-speaking classification of minerals according to Dana assigns the Painite in the class of " oxides and hydroxides " and there in the department of " multiple oxides ". Here he can be found as the only member of the unnamed group 07:05:02 within the sub-division of " multiple oxides with the formula ABX2 ".
Education and Locations
The mineral was discovered in the early 1950s in Burma (now Myanmar). Prior to 2001, only 3 crystals with a weight of less than 3.5 grams were collectively known. Between 2001 and 2004 more than 14 specimens were found. In 2005 it was one of the primary deposits in Ohngaing and later the richer deposits in Wetloo. Meanwhile, several thousand copies have been having an individual weight of up to about 500 grams found. Most of the pieces are cracked or been penetrated by limonite or ruby. Pieces with end faces or clear sandable copies are still very rare.
Most of them are pieces from the highly weathered near-surface layer. The pieces are then often interspersed with limonite. Although Painite itself is extremely weather resistant, but the tears are filling up fast with the brown mineral. Furthermore, many Painite with ruby are associated, or even because of the similar composition ( Painite has a very high alumina content ) into ruby.
Except at its type locality Ohngaing and Wetloo the mineral was found in Kachin State only in Nanyazeik in Myitkyina District.
Crystal structure
Painite crystallized hexagonal space group P63 ( Raumgruppen-Nr. 173) with the lattice parameters a = 8.72 Å and c = 8.47 Å and two formula units per unit cell.
Use as a gemstone
Painite and good physical properties, due to its extreme rarity, partially processed to valuable gemstones or degraded due to the high demand among mineral collectors specially for collection purposes and exported as blanks. Other uses do not exist.