Thulite | |
---|---|
General | |
Category | Sorosilicate variety |
Formula (repeating unit) | (Ca,Mn)2Al3(SiO4)(Si2O7)O(OH) |
Crystal system | Orthorhombic |
Identification | |
Color | Pink |
Crystal habit | Massive |
Cleavage | Perfect {010} imperfect {100} |
Fracture | Uneven to conchoidal |
Mohs scale hardness | 6.5 |
Luster | Vitreous, pearly on cleavage surfaces |
Streak | White or colorless |
Specific gravity | 3.10–3.38 |
Optical properties | biaxial positive |
Refractive index | 1.69–1.70 |
Birefringence | 0.006–0.018 |
Pleochroism | Present, dichroism or trichroism depending on color. |
Thulite (sometimes called rosaline) is a translucent, crystalline or massive pink manganese-bearing variety of the mineral zoisite. Manganese substitutes for calcium in the structure with up to two percent Mn2+. [1] Thulite is often mottled with white calcite and occurs as veins and fracture fillings transecting many types of rock. In mineralogical literature, thulite may sometimes refer to any pink zoisite. Clinothulite is the manganese bearing variety of monoclinic clinozoisite. [2]
Thulite was first discovered at a place called Sauland in Telemark county, Norway in 1820. [3] It is named after the mythical island of Thule in the belief that the island is Scandinavia. [3] Thulite is used as a gemstone and carving material in the manufacture of jewelry and ornamental objects.
Thulite is also found in the Austrian Tyrol and in Mitchell County, North Carolina. A new, more recent find of a small quantity of thulite was discovered near Riverside in Okanogan County, Washington, US [3] and in Snillfjord Municipality in Trøndelag county, Norway during tunnel constructions in December 2018. [4] Thulite is also found in New Zealand in the Otago region of the South Island.
Thulite is also found in Namibia. The occurrence is spread throughout the Namib Desert and generally has ridges with a NE to SW setting. The color can be highly variable with most deposits being greenish in nature, but on occasion the desirable pink color is to be found.[ citation needed ]
Beryl ( BERR-əl) is a mineral composed of beryllium aluminium silicate with the chemical formula Be3Al2Si6O18. Well-known varieties of beryl include emerald and aquamarine. Naturally occurring hexagonal crystals of beryl can be up to several meters in size, but terminated crystals are relatively rare. Pure beryl is colorless, but it is frequently tinted by impurities; possible colors are green, blue, yellow, pink, and red (the rarest). It is an ore source of beryllium.
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO2. Quartz is, therefore, classified structurally as a framework silicate mineral and compositionally as an oxide mineral. Quartz is the second most abundant mineral in Earth's continental crust, behind feldspar.
Tourmaline is a crystalline silicate mineral group in which boron is compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. This gemstone comes in a wide variety of colors.
Hornblende is a complex inosilicate series of minerals. It is not a recognized mineral in its own right, but the name is used as a general or field term, to refer to a dark amphibole. Hornblende minerals are common in igneous and metamorphic rocks.
Lepidolite is a lilac-gray or rose-colored member of the mica group of minerals with chemical formula K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2. It is the most abundant lithium-bearing mineral and is a secondary source of this metal. It is the major source of the alkali metal rubidium.
Rhodochrosite is a manganese carbonate mineral with chemical composition MnCO3. In its pure form (rare), it is typically a rose-red colour, but it can also be shades of pink to pale brown. It streaks white, and its Mohs hardness varies between 3.5 and 4.5. Its specific gravity is between 3.45 and 3.6. The crystal system of rhodochrosite is trigonal, with a structure and cleavage in the carbonate rhombohedral system. The carbonate ions (CO2−
3) are arranged in a triangular planar configuration, and the manganese ions (Mn2+) are surrounded by six oxygen ions in an octahedral arrangement. The MnO6 octahedra and CO3 triangles are linked together to form a three-dimensional structure. Crystal twinning is often present. It can be confused with the manganese silicate rhodonite, but is distinctly softer. Rhodochrosite is formed by the oxidation of manganese ore, and is found in South Africa, China, and the Americas. It is one of the national symbols of Argentina and the state of Colorado.
Serpentine subgroup are greenish, brownish, or spotted minerals commonly found in serpentinite. They are used as a source of magnesium and asbestos, and as decorative stone. The name comes from the greenish color and smooth or scaly appearance from the Latin serpentinus, meaning "snake-like".
Zoisite, first known as saualpite, after its type locality, is a calcium aluminum hydroxy sorosilicate belonging to the epidote group of minerals. Its chemical formula is Ca2Al3(SiO4)(Si2O7)O(OH).
Anyolite is a metamorphic rock composed of intergrown green zoisite, black/dark green pargasite and ruby. It has been found in the Arusha Region of Tanzania and in Austria. It is sometimes incorrectly advertised as a variety of the mineral zoisite. The term anyolite is, however, not an officially accepted term for a metamorphic rock. Its name derives from the Maasai word anyoli, meaning "green". Anyolite is also referred to as ruby in zoisite, ruby zoisite, ruby-zoisite or Tanganyika artstone.
Epidote is a calcium aluminium iron sorosilicate mineral.
Smithsonite, also known as zinc spar, is the mineral form of zinc carbonate (ZnCO3). Historically, smithsonite was identified with hemimorphite before it was realized that they were two different minerals. The two minerals are very similar in appearance and the term calamine has been used for both, leading to some confusion. The distinct mineral smithsonite was named in 1832 by François Sulpice Beudant in honor of English chemist and mineralogist James Smithson (c. 1765–1829), who first identified the mineral in 1802.
Rhodonite is a manganese inosilicate, with the formula (Mn, Fe, Mg, Ca)SiO3, and member of the pyroxenoid group of minerals, crystallizing in the triclinic system. It commonly occurs as cleavable to compact masses with a rose-red color (its name comes from Ancient Greek ῥόδον (rhódon) 'rose'), often tending to brown due to surface oxidation. The rose-red hue is caused by the manganese cation (Mn2+).
Vesuvianite, also known as idocrase, is a green, brown, yellow, or blue silicate mineral. Vesuvianite occurs as tetragonal crystals in skarn deposits and limestones that have been subjected to contact metamorphism. It was first discovered within included blocks or adjacent to lavas on Mount Vesuvius, hence its name. Attractive-looking crystals are sometimes cut as gemstones. Localities which have yielded fine crystallized specimens include Mount Vesuvius and the Ala Valley near Turin, Piedmont.
Andradite is a mineral species of the garnet group. It is a nesosilicate, with formula Ca3Fe2Si3O12.
Clinozoisite is a complex calcium aluminium sorosilicate mineral with formula: Ca2Al3(Si2O7)(SiO4)O(OH). It forms a continuous solid solution series with epidote by substitution of iron(III) in the aluminium (m3 site) and is also called aluminium epidote.
Sauland is the administrative centre of Hjartdal Municipality in Telemark county, Norway. The village is located at the confluence of the Hjartdøla and Skogsåa rivers, which together form the river Heddøla. The European route E134 highway runs through the village. The village of Hjartdalsbygda lies about 16 kilometres (9.9 mi) to the west, the village of Tuddal lies about 20 kilometres (12 mi) to the north, the village of Gransherad lies about 12 kilometres (7.5 mi) to the northeast, the village of Heddal lies about 15 kilometres (9.3 mi) to the east, and the town of Notodden lies about 20 kilometres (12 mi) to the east.
Serandite is a mineral with formula Na(Mn2+,Ca)2Si3O8(OH). The mineral was discovered in Guinea in 1931 and named for J. M. Sérand. Serandite is generally red, brown, black or colorless. The correct name lacks an accent.
Caryopilite (synonymous with ectropite and ektropite) is a brown-colored mineral with formula (Mn2+,Mg)3Si2O5(OH)4. The mineral was discovered in 1889 from a mine in Sweden. It was named for the Greek words for walnut and felt in reference to its appearance.
Manganopyhllite is a manganese-rich variety of biotite. It was first discovered in the Harstigen mine in Sweden. The mineral was first described in 1890. The earliest use is from Edward Dana.
Colophonite, less commonly kalophonit (from Ancient Greek: κολοφωνία, kolophonia, rosin or rosin colors) — an obsolete historical name for a brownish calcium-iron mineral of the garnet family, a variety of grossular (later, andradite), discovered as an associated metamorphic mineral in the iron ore mines of the southern Norwegian islands, primarily Tromø (near Arendal). It is a nesosilicate, with formula Ca3Fe3+2(SiO4)3. Other names for colophonite: resin garnet (French: Grenat résinite), calderite, rosin garnet.