#borate

Locality: Pöhla-Tellerhäuser Mine, Schwarzenberg, Erzgebirge, Saxony, Germany

Boron is a chemical element with the symbol B and atomic number 5. Produced entirely by cosmic ray spallation and supernovae and not by stellar nucleosynthesis, it is a low-abundance element in the Solar system and in the Earth's crust.[13] Boron is concentrated on Earth by the water-solubility of its more common naturally occurring compounds, the borate minerals. These are mined industrially as evaporites, such as borax and kernite. The largest known boron deposits are in Turkey, the largest producer of boron minerals. Borax, its mineral form then known as tincal, glazes were used in China from AD 300, and some crude borax reached the West, where the Perso-Arab alchemist Jābir ibn Hayyān apparently mentioned it in AD 700. Marco Polo brought some glazes back to Italy in the 13th century. Agricola, around 1600, reports the use of borax as a flux in metallurgy. In 1777, boric acid was recognized in the hot springs (soffioni) near Florence, Italy, and became known as sal sedativum, with primarily medical uses. Boric acid has antiseptic, antifungal, and antiviral properties and for these reasons is applied as a water clarifier in swimming pool water treatment.[111] Mild solutions of boric acid have been used as eye antiseptics. Boron is an essential plant nutrient, required primarily for maintaining the integrity of cell walls. However, high soil concentrations of greater than 1.0 ppm lead to marginal and tip necrosis in leaves as well as poor overall growth performance. Levels as low as 0.8 ppm produce these same symptoms in plants that are particularly sensitive to boron in the soil. Nearly all plants, even those somewhat tolerant of soil boron, will show at least some symptoms of boron toxicity when soil boron content is greater than 1.8 ppm. When this content exceeds 2.0 ppm, few plants will perform well and some may not survive. The average cost of crystalline boron is $5/g.[71] Free boron is chiefly used in making boron fibers, where it is deposited by chemical vapor deposition on a tungsten core (see below). Boron fibers are used in lightweight composite applications, such as high strength tapes. This use is a very small fraction of total boron use. Boron is introduced into semiconductors as boron compounds, by ion implantation.

Johachidolite Here we have a rare calcium aluminium borate found so far in only 2 places on Earth, being named after a colonial Japanese name for the district (now North Korean) where it was first found. It varies from colourless, through the yellow-orange found here to light green, and while the Mohs hardness of 7.5 makes it facetable for jewellery use, rough material is too uncommon for it to become well known outside collecting circles. It crystallises from magmas that are low in silica, in the case of the type locality a dyke rich in the mineral Nepheline has intruded into and baked a limestone, forming an exotic mineral rich stew called a skarn. Due to traces of rare earth elements incorporated into the crystal structure it displays intense blue fluorescence in UV light (for an explanation of this phenomenon see http://bit.ly/1GPmnMy). The 1.6 x 1.3 x 1.2 cm specimen in the photos was mined in the other locality, source of all the world class or gem grade material found so far, the Mogok Stone Tract of Burma (see http://bit.ly/2hlbhOj and http://bit.ly/2zDHbgl). Loz Image credit: Rob Lavinsky/iRocks.com https://www.mindat.org/min-2101.html https://www.gemdat.org/gem-2101.html http://bit.ly/2iBIEwm

weight 24g/120cts & dimensions 32x23x18mm