A popular guide to minerals : with chapters on the Bement Collection of minerals in the American Museum of Natural History, and the development of mineralogy . Fig. 207 Fig. 208 Fig. 209 w Fig. 210 When crystals twin together in a repetitive series, first two,then a third, then a fourth and so on, the process is called repeatedtwinning. Such repetition may produce a closed (cyclical) angularring (Fig. 211, rutile) or an extended crystal in a linear arrange-.

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Keywords: ., bookcentury1900, bookdecade1910, booksubjectmineral, bookyear1912