为了保证工业的发展,需要建立足够的稀有元素原料基地,这就决定了稀有元素地球化学研究的广泛范围。稀有元素依其本身的结晶化学性质,可明显地将其分为两个组:易富集的元素和分散的、几乎不形成其独立矿物的元素,这一观点近来已被接受。 我所提出的地壳中0.001％的假定含量介限作为稀有标准,也包括象银、砷等尽管在地壳中含量低, In order to ensure the development of industry, there is a need to establish a sufficient base of rare element raw materials, which determines the broad scope of rare element geochemical research. The idea that rare elements, according to their own crystalline chemistry, can be apparently divided into two groups: readily available elements and dispersed elements that scarcely form their own minerals, has recently been accepted. The proposed limit of 0.001% of the hypothetical content in the crust I proposed as a rare standard also includes silver, arsenic, etc., although low in the crust,