PSEUDOMORPH literally means "false form" and is used in mineralogy to indicate that a mineral has the outward appearance of a different mineral. In mineralogical terminology the phrase "mineral X after mineral Y", would be used; as in Copper after Aragonite.
This specimen is a copper
pseudomorph after aragonite. The aragonite crystal was dissolved leaving a
pocket that was latter filled with copper. This is commonly called a "FILLING
PSEUDOMORPH".
In a similar fashion,
this quartz pseudomorph after aragonite was formed.
This specimen represents an
encrustation of chalcedony over aragonite crystals. The aragonite crystals
have since dissolved away leaving just the durable crust. This is commonly
called an "ENCRUSTATION
PSEUDOMORPH"
This cluster of
vanadinite crystals has replaced a wulfenite crystal. This type of
pseudomorph is called a "REPLACEMENT PSEUDOMORPH"
This specimen is from the Rowley Mine, AZ.
Hematite after Pyrite
Hematite after Marcasite, White Desert
Egypt
Limonite after Garnet from
Patagonia, AZ
Quartz encrusting Calcite from
Camp Verde, AZ
Malachite after Azurite