a mineral that is a complex borosilicate and hydroxide of aluminum containing iron and magnesium and calcium and lithium and sodium; it is usually black but occurs in transparent colored forms that are used as gemstones
例句
用作名词 (n.)
Never use chemicals such as hydrofluoric acid or ammonium fluoride to clean Tourmaline because it can erode the stone. 从来不使用化学物质如氢氟酸或氟化铵清洁电气石，因为它可以削弱石头。
The main anionic finishing agents applied in textiles are tourmaline and natural ores with micro-pores and lanthanon. 纺织品中应用的负离子整理剂主要为电气石和加稀土元素的天然超微多孔质矿石。
美
['tʊəməlɪn]
