Leifite
Leifite is a tectosilicate that is rare. Tectosilicates are designed on a framework of tetrahedra with silicon or aluminium in the oxygen and center in the vertices; they include feldspars and zeolites, but leifite will not belong either in among these categories. It really is a part regarding the group that is leifite which includes telyushenkoite (Cs, Na, K)Na6(Be2Al3Si15O39) and eirikite KNa6Be2(Si15Al3)O39F2. Leifite was discovered in 1915, and named after Leif Ericson who was simply a Norse explorer who lived around 1000 AD and was most likely the first European to land in North America, nearly 500 years before Christopher Columbus. Eirikite was named in 2007 after Eirik Raude, or Erik the Red, (950–1003), who discovered Greenland and who was simply the paternal father of Leif Ericson. The mineral that is third the group, telyushenkoite, was discovered in 2001. It absolutely was not named after any one of Leif Ericson’s family relations but after a professor of geology in Turkmenistan. Leifite is a mineral that is trigonal class 3 2/m, space group P3m1. You can find 3 formula units when you look at the unit cell (Z = 3), and cell dimensions are 14.4 Å when you look at the direction and 4.9 Å into the direction that is c. It includes groups that are OH but no water of crystallization as once was assumed. Tetrahedrons of silicon or atoms enclosed by four oxygen atoms backlink to form six-membered rings stacked over the direction that is c form channels, comparable to those who work in zeolites.
When comes its appearance leifite is typically white or colourless, with a white streak and a silky or luster that is vitreous. It occurs as tiny needles making up aggregates that are radiating rosettes. Individual crystals are deeply striated prisms that are hexagonal are transparent to translucent. Leifite is definitely a beryllium that is a rare mineral that is situated in cavities of igneous stones that have high levels of alkali metals, particularly sodium, and low concentrations of silicon and aluminum and contain little or no Quartz. There are just three locations that are understand finding Leifite: Narsarsuk, Greenland; Lovozero massif, and Khibiny massif, Kola Peninsula, Russia; and Mont Saint-Hilaire, Quebec, Canada. The origin that is mainly of small) gemmy crystals could be the Poudrette quarry Mont Saint-Hilaire, Rouville County, Québec, Canada.
| Category: | Silicate mineral |
| Formula: | Na7Be2(Si15Al3)O39(F,OH)2 |
| Crystallography: | Trigonal – Hexagonal Scalenohedral |
| Crystal Habit: | Crystals hexagonal prisms, acicular and deeply striated, to 3 cm. In radiating fibrous masses and spherical aggregates. |
| Twinning: | None |
| Cleavage: | [1010] Distinct |
| Fracture: | Uneven to Splintery |
| Tenacity: | Brittle |
| Hardness (Mohs): | 6.0 |
| Density: | 2.57 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Not Radioactive |
| Color: | Colorless, White |
| Transparency: | Transparent to Translucent |
| Luster: | Vitreous, Silky |
| Refractive Index: | 1.511 – 1.522 Uniaxial ( + ) |
| Birefringence: | 0.0107 |
| Dispersion: | None |
| Pleochroism: | None |
