Ferri-Katophorite
The Katophorite minerals are sodium-calcium Amphiboles with varying amounts of magnesium (Mg), iron (Fe) and alumiunum (Al). The kinds of Katophorite are known as according to their chemical composition. Examples are: Ferri-Katophorite is called for its iron that is ferric dominance Ferro-Katophorite is known as for its ferrous iron dominance; Magnesio-Katophorite is named for its magnesium dominance, an such like. Truth be told there are nine varieties with Katophorite as various element title modifiers to their base name.
The Kataphorite Group species magnesium that is containingMg) along with ferric iron (Fe3+) greater than aluminum (Al) within the C place ended up being called Magnesio-Katophorite in the 1978 and 1997 IMA amphibole nomenclature. Nevertheless, the Katophorite Group minerals had been redefined in the 2012 IMA amphibole nomenclature. The 2012 change renamed the Mg, Fe3+ and (OH) member that is dominant of group Ferri-Katophorite.
The mineral Katophorite ended up being first described by W.C. Brøgger (1894) as an mineral that is amphibole he available at three localities in the Permian Oslo Region, Norway. The minerals originally designated by Brøgger (1894) as “Katophorite” are, based on the Amphibole that is new nomenclature classified as Ferro-Katophorite. Katophorite, with no element modifiers, is the name provided to an Amphibole occurance found in 2013 at the Hpakant-Tawmaw Jade Tract, Hpakant Township, Mohnyin District, Kachin State, north Myanmar (Burma). Katophorite is named from the Greek word
κατώφορος (kataphora) meaning carrying down, in allusion to its volcanic origin.
Katophorite is usually black, dark greenish bluish or black black colored with vitreous luster and usually opaque but are often transparent to translucent in thin slivers. Black Katophorite is normally discovered associated with greenish arfvedsonite that is black colored white Feldspar, and red Eudialyte during the Kipawa alkaline complex in Canada (see gem pictured above). This makes for a very unusual and gem that is attractive.
Circulation: might occur in the Oslo (Christiania) region, Norway, from where it ended up being originally described. On the Rallier-du-Baty Peninsula, Kerguelen Island, into the Indian that is south Ocean. In the Kipawa alkaline complex, Les Lacs-du-Témiscamingue, Témiscamingue RCM, Abitibi-Témiscamingue, Québec, Canada. At the Hpakant-Tawmaw Jade Tract, Hpakant Township, Mohnyin District, Kachin State, northern Myanmar (Burma).
| Chemical Formula: | Na[NaCa][(Fe2+,Mg)4Al](Si7Al)O22(OH)2 |
| Sodium Calcium Iron Magnesium Aluminum Silicate Hydroxide | |
| Emperical Chemical Formula: | Na1.2K0.3Ca1.3Fe2+3.25Mg1.5Ti0.2Mn2+0.2Al0.7Si7.3O22(OH)22 |
| Molecular Weight: | 939.86 gm |
| Composition: | Potassium | 1.25 % | K | 1.50 % | K2O |
| Sodium | 2.94 % | Na | 3.96 % | Na2O | |
| Calcium | 5.54 % | Ca | 7.76 % | CaO | |
| Magnesium | 3.88 % | Mg | 6.43 % | MgO | |
| Titanium | 1.02 % | Ti | 1.70 % | TiO2 | |
| Manganese | 1.17 % | Mn | 1.51 % | MnO | |
| Aluminum | 2.01 % | Al | 3.80 % | Al2O3 | |
| Iron | 19.31 % | Fe | 24.84 % | FeO | |
| Silicon | 21.81 % | Si | 46.67 % | SiO2 | |
| Hydrogen | 0.21 % | H | 1.92 % | H2O | |
| Oxygen | 40.86 % | O | |||
| 100.00 % | 100.09 % | = TOTAL OXIDE |
| Crystallography: | Monoclinic – Prismatic |
| Crystal Habit: | Prismatic, granular, also as fibrous aggregates or dendrites and skeletal crystals. Commonly rimming other minerals. |
| Twinning: | || {100} |
| Cleavage: | Perfect on {110}, intersecting at ~56° and ~124°; parting on {010} |
| Fracture: | Conchoidal |
| Tenacity: | Brittle |
| Moh’s Hardness: | 5.0 – 6.0 |
| Density: | 3.2 – 3.5 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Not Radioactive |
| Color: | Black, dark green-black, bluish black; reddish yellow, bluish green in thin section |
| Transparency: | Transparent to translucent, opaque |
| Luster: | Vitreous |
| Refractive Index: | 1.640 – 1.692 Biaxial ( – ) |
| Birefringence: | 0.020 |
| Dispersion: | Strong, r < v |
| Pleochroism: | Strong; reddish yellow, reddish brown, and dark green to black |
| Anisotropism: | n/a |
