A borate with the chemical composition Na 2 B 4 O 7 ・10H 2 O. The crystals belong to the monoclinic system and are usually colorless or white with a short columnar shape. They are completely cleaved on {100}, have a vitreous luster, and have shell-like fractures. Mohs hardness is 2-2.5, specific gravity is 1.7. They occur naturally in the form of lumps or films. They are the most common borate mineral and are found in dry areas due to the evaporation of salt lakes. Famous deposits are found in Turkey, California in North America, and the Andes in South America. Boron extracted from various borate minerals is generally commercialized in the form of borax. Source: Heibonsha World Encyclopedia, 2nd Edition Information |
Na2B4O7・10H2Oの化学組成をもつホウ(硼)酸塩。結晶は単斜晶系に属し,通常無色あるいは白色で,短柱状の外形を示す。{100}にへき開完全,ガラス光沢,断口は貝殻状。モース硬度2~2.5,比重1.7。天然には塊状あるいは皮膜状としても産する。最も普遍的なホウ酸塩鉱物で,塩湖の蒸発などにより乾燥地帯に産出する。トルコ,北アメリカのカリフォルニア,南アメリカのアンデスなどに有名な鉱床がある。種々のホウ酸塩鉱物から抽出されるホウ素は一般にホウ砂の形で商品化される。
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