Abstract: Valleriite belongs to trigonal mineral with the characteris-tics of interlayering sulfide (Cu, Fe)S and brucite (Mg, Fe)(OH)₂ layers. Previous study proposes a superlattice hypothesis both on the c- and a-axes due to the mismatch of the sulfide and brucite lattices. The size of the superlattice depends on the value of mismatch of the two sub-unit cells. However TEM study on valleriite shows that it is of textural structure with no indication of presence of superlattice diffractions on a-axis, nor on c-axis. Along c-axis valleriite presents ruther well orderdinterlayering properties, showing a strong 1.14nm reflection, whereas along a-axis splits streaks of reflections occurred, indicating mis-orientation of brucite arrangement with respect to sulfide. Valleriite is formed as the result of the alteration of pyrite or chalcopyrite withthe initial process of forming about 10nm size micro-crystals of (Cu, Fe)Ssulfides. Later those micro-crystals of sulfides react with serpentines to obtain brucite layers to finally producing valleriite.

Key words: valleriite, crystal structure, TEM, Laiyuan, Hebei Province

摘要： 墨铜矿的结构属三方晶系，为典型的异类矿物结构基元层间层矿物^[1]。结构以硫化物层（Cu，Fe）S和似水镁石层(Mg，Fe)(OH)₂呈规则交互而构成。这种共价键和离子键共存、亲硫元素与亲氧元素在一起的现象是不多见的。这不同于层状硅酸盐中出现的间层（均为同类的硅酸盐）。过去的研究^[2]认为硫化物层和似水镁石层由于结构失配而产生超晶胞，超晶胞大小为ａ和ｃ轴方向失配度的公度因子。我们利用高分辨电子显微镜研究墨铜矿的结果表明，它是具有织构性质的矿物，沿ｃ轴方向间层规则交互出现，产生1.14nm的衍射点，而沿a轴的层方向出现弧形弥散线，且硫化物层和似水镁石层有各自独立的弥散线，不构成超晶胞。墨铜矿是由黄铁铜或黄铜矿蚀变而成，黄铁矿或黄铜矿首先形成10nm大小的超微晶，再与蛇纹石反应，蛇纹石去硅而将(Mg, Fe)(OH)₂层与硫化物层规则间层而造成了墨铜矿的结构。

关键词: 墨铜矿, 晶体结构, 透射电镜, 河北涞源