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.


from Wiktionary, Creative Commons Attribution/Share-Alike License

pseudo- (“false”) + -morph (“form”)


  • It is then called a pseudomorph, which is a term applied to any mineral which, instead of having the form it should possess, shows the form of something which has altered its structure completely, and then disappeared.

    The Chemistry, Properties and Tests of Precious Stones

  • So would you consider mineral replacement like a malachite pseudomorph after calcite to fit the preference to photographs that depict “invasive species.”

    Photography contest, II - The Panda's Thumb

  • It will help to mesh awarenesses with a human, Djana ¦ no terrified captive, no lickspittle turncoat, no sniveler about peace and brotherhood, no pseudomorph grown up among us apart from his own breed ¦ but one who has come to me freely, out of the depths of the commonalty that bred her, one who has known alike the glory and the tragedy of being human.

    A Circus of Hells

  • For instance: very often, in a certain cavity, fluorspar has existed originally, but, through some chemical means, has been slowly changed to quartz, so that, as crystals cannot be changed in shape, we find quartz existing -- undeniably quartz -- yet possessing the crystals of fluorspar; therefore the quartz becomes a pseudomorph, the condition being an example of what is termed pseudomorphism.

    The Chemistry, Properties and Tests of Precious Stones

  • Hawksnest, over beyond, I noted, had its pseudomorph too; a newspaper proprietor of the type that hustles along with stolen ideas from one loud sink-or-swim enterprise to another, had bought the place outright; Redgrave was in the hands of brewers.

    Tono Bungay

  • I conceive it as a mechanism set going by heat -- as a sort of active crystal with the capacity of giving rise to a great number of pseudomorphs; and I conceive that external conditions favour one or the other pseudomorph, but leave the fundamental mechanism untouched.

    Life and Letters of Thomas Henry Huxley — Volume 2

  • It'll make that pseudomorph page just sing , I'm sure.



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  • Merriam-Webster Dictionary:

    Pronunciation: \ˈsü-də-ˌmȯrf\

    Function: noun

    Etymology: probably from French pseudomorphe, from pseud- + -morphe -morph

    Date: 1849

    1 : a mineral having the characteristic outward form of another species

    2 : a deceptive or irregular form

    February 14, 2008