Editing Pseudomorph (section)

==Paramorph==
[[File:Acanthite-Argentite-gld28a.jpg|left|thumb|Cubic crystals of argentite transformed into acanthite (monoclinic), without any external visible change. Specimen from the San Juan de Rayas Mine, Guanajuato, Mexico. 3 cm. ]]
A '''paramorph''' (also called '''allomorph''') is a mineral changed on the molecular level only when the structure of a mineral transitions to a more stable polymorph.  It has the same chemical composition, but with a different structure. For example, the cubic form of silver sulfide, argentite, does not actually exist below 173°C, and all are pseudomorphized into the monoclinic mineral acanthite. When the structure is very different, as in the aragonite and calcite, the unstable mineral can remains indefinitely in a metastable form, although transformation can occur under some conditions.  Usually, the mineral looks identical to the original, unaltered form.