pseudomorph
/ˈsjuːdə(ʊ)mɔːf
/Crystallography
noun
A crystal consisting of one mineral but having the form of another.In one isolated occurrence, aggregates of small cerussite crystals form pseudomorphs, less than 2 mm across, after an unknown mineral....
- The idea that tiger's-eye is a pseudomorph - a mineral in which crystals of one material take on the form of another, which it replaces atom by atom - held sway for more than 125 years.
- Amazing and fantastic forms of representatives of the mineral world are displayed in the exhibitions dedicated to crystals, mineral aggregates, and pseudomorphs.
verb [with object]
Replace (another substance) to form a pseudomorph: actinolite and hornblende typically pseudomorph pyroxene...
- Andalusite porphyroblasts that overgrow the S 1 fabric were pseudomorphed by colourless mica.
- Foord reported that bastnasite has been found pseudomorphing allanite.
- Relict coarse, lath-shaped omphacites are variably preserved, but all are either partially retrogressed to pargasite or have been pseudomorphed by diopside-plagioclase symplectites.
Derivatives
pseudomorphic
- Any or all of these carbonate minerals may have acted as the now-replaced parent to the well-known pseudomorphic, rhombohedral replacements by hematite and goethite.
- As the dimensions of materials are reduced to the nanometer scale, the stabilization of pseudomorphic crystal structures that differ from their bulk equilibrium phases can occur. The pseudomorphic growth could provide a substantially larger bulk modulus and greater hardness than the average of the constituent materials in nanolayered and nanocomposite thin films.
pseudomorphism
- Although this is not a particularly quantitative test, it does show that complete pseudomorphism (quartz sand after calcite) had not occurred for these two specimens.
- The absence of euhedral crystals of phillipsite, even by SEM examination, suggests that the alteration may be a form of pseudomorphism.
pseudomorphous
- Whenever this layer is found, collectors know to look carefully below it for highly silicified wood and nodules (either as agate fortifications or pseudomorphous replacement of barite concretions).
- The outer zone of the alteration halo is most extensively developed in the semi-pelitic schists, and is manifested by the pseudomorphous replacement of biotite by chlorite, rutile and quartz, and feldspar by sericite.
Origin
Mid 19th century: from pseudo- 'false' + Greek morphē 'form'.