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  • 館藏編號:NTUG010-T300044
  • 題名:Igneous Rocks
  • 作者:阮維周
  • 藏品形式:稿本
  • 尺寸:210X297(mm)
  • 簡述:P.42
  • 內容:

    P.42 silicates. (3) Included (foreign) minerals - rock fragments or minerals. Primary minerals are limited to a very few groups, such as feldspars, pyriboles, micas, quartz, olivine, and feldspathoids. As a rule, only one generation of feldspar is found in a certain rock. There are two exceptions to this rule: (l) the plagioclase, which is intergrown with orthoclase as micro-perthite, may be differ from the independently formed plagioclase crystals, (2) where several members of the series occur together in zonal crystals. In this case all the crystals of same generation are zonal and similar. Pyroxene, amphibole and mica may be of more than one kind, as to olivine, there is mostly only one kind. - 15 -