Howlite
Howlite, a calcium borosilicate hydroxide (Ca2B5SiO9(OH)5), is a borate mineral discovered among evaporite deposits. Howlite was found close to Windsor, Nova Scotia in 1868 by Henry How (1828–1879), a Canadian chemist, geologist, then mineralogist. How was alerted in imitation of the unknown metal with the aid of miners into a gypsum quarry, whosoever found that in conformity with be a nuisance. He called the new metal silico-boro-calcite; such was once attached the fame howlite with the aid of James Dwight Dana rapidly thereafter. The most frequent structure of howlite is irregular nodules, once in a while corresponding to cauliflower. Crystals on howlite are rare, having been found in only a couple localities worldwide. Crystals had been forward referred to besides Tick Canyon within the Sierra Pelona Mountains regarding California, or additional at Iona, Nova Scotia. Crystals reach the most bulk on as regards certain centimeter. The nodules are white including satisfactory grey and black veins among an erratic, frequently web-like pattern, opaque along with a sub-vitreous luster. The crystals at Iona are colorless, pure or brown yet are often translucent yet transparent. Its structure is monoclinic with a Mohs solidity of 3.5 yet lacks regular cleavage. Crystals are prismatic and flattened of {100}.The crystals beyond Tick Canyon are elongated along the 010 axis, whilst those beyond Iona are elongated along the 001 axis.
Howlite is many times used after performing decorative objects such as short carvings or jewelry components. Because regarding its porous texture, howlite may be effortlessly dyed in conformity with imitate other minerals, especially turquoise due to the fact on the superficial similarity about the veining patterns. Howlite is additionally sold within its natural state, every so often underneath the deceptive trade names of “white turquoise” and “white buffalo turquoise,” or the derived name “white buffalo causeway. Oftentimes, if the reality were known, Howlite would be better known as a Turquoise immitation. Howlite is frequently (and incredibly convincingly) dyed blue to pass as Turquoise. It even contains gray to black threadlike impurities resembling the veining in Turquoise. A source that is present of is Cape Breton Island, Victoria County, Nova Scotia, Canada although these crystals are not suitable for faceting. The sort that is massive be located at the Sterling Borax Mine, Tick Canyon, Lang, l. a. County, Ca, USA (and a few other California locations); Magdalena, Sonora, Mexico; Susurluk, Turkey; Baljevac na Ibru, near Kraljevo, and near Bela Stena, Yugoslavia.
| Category: | Inoborates |
| Formula: | Ca2B5SiO9(OH)5 |
| Crystallography: | Monoclinic – Prismatic |
| Crystal Habit: | Crystals tabular, flattened, to 1 cm. Most commonly nodular. When massive, chalky to porcelaneous. |
| Twinning: | None |
| Cleavage: | None |
| Fracture: | Even and Smooth in porcelaneous types |
| Tenacity: | Brittle |
| Moh’s Hardness: | 3.5 |
| Density: | 2.53 – 2.59 (g/cm3) |
| Radioactivity: | Not Radioactive |
| Color: | White with Black veins in massive form; pale Brown translucent crystals |
| Transparency: | Usually Opaque, Translucent on thin edges |
| Luster: | Sub-Vitreous, Porcelaneous, Earthy |
| Refractive Index: | 1.58 – 1.60 Biaxial ( – ) |
| Birefringence: | 0.0200 |
| Dispersion: | None |
| Pleochroism: | None |
