from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A false, deceptive, or irregular form.
- n. A mineral that has the crystalline form of another mineral rather than the form normally characteristic of its own composition.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. 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.
from the GNU version of the Collaborative International Dictionary of English
- n. An irregular or deceptive form.
- n. A pseudomorphous crystal, such as a crystal consisting of quartz, but having the cubic form of fluor spar, the fluor crystal having been changed to quartz by a process of substitution.
from The Century Dictionary and Cyclopedia
- n. A deceptive, irregular, or false form; specifically, in mineralogy, a mineral having a definite form belonging, not to the substance of which it consists, but to some other substance which has wholly or partially disappeared.
pseudo- (“false”) + -morph (“form”) (Wiktionary)