Sentence:  The first kind of <WSD>pseudomorphs</WSD>, are <WSD>pseudomorphs</WSD> by alteration; the second, <WSD>pseudomorphs</WSD> by replacement; the third, <WSD>pseudomorphs</WSD> by infiltration; the fourth, <WSD>pseudomorphs</WSD> by incrustation. 
Meaning of the word marked with <WSD> tags:  A mineral that formed by replacement of an existing mineral (or organic matter) such that the new mineral has the appearance and dimensions of the original.