Note 112 — Chapter VI · THE PHOSPHATES AND HALIDES
Reading edition
Zeitsch. Kryst. Min. 1901, 34, 268.
[113] One mineral is said to be pseudomorphous after another when the first is produced from the second by a chemical change which proceeds so slowly that the original structure and crystalline form are unaltered (i.e. a change proceeding molecule by molecule). The pseudomorph is usually opaque and shows clear signs of the alteration.