According to geological nomenclature, these are pseudomorphs
, "false forms": minerals that, as a result of substitution or alteration, have the appearance of other minerals, despite being compositionally different.
Foster (1981) determined that muscovite and biotite pseudomorphs
after staurolite formed as a result of sillimanite nucleation that sets up chemical potential gradients between the growing sillimanite, pre-existing staurolite, and the rock matrix of biotite, muscovite, plagioclase, quartz, ilmenite, and garnet.
In most cases the hornblende is completely altered to chlorite and epidote and pseudomorphs
after hornblende are well noticed.
Approximately 40 kg of rough material were recovered from a silicified zone of the deposit, which also contained chalcedony pseudomorphs
after barite, calcite and other minerals.
Soft rot decay and wood pseudomorphs
in an ancient coffin (700 BC) from tumulus MM at Gordion, Turkey.
The mineral assemblage includes clinopyroxene, plagioclase, opaque minerals, and smectites (probably pseudomorphs
Later during periods of fluvial, more oxidizing conditions, they were oxidized to goethite-hematite pseudomorphs
The expanded study of textile imprints and pseudomorphs
also contributes to our understanding of ancient textiles, as do new analytical methods and scientific analyses.
Actually, in my next lecture I plan to show "Map" upside down alongside Cezanne's hat and "Mont Sainte-Victoire," partly because I've come to believe over time that there are no pseudomorphs
in visual art.
Iron oxide pseudomorphs
after chalcopyrite make Emu Plain an exciting drill target.
Warren, personal communication, 2007), and pseudomorphs
preserved in local strata demonstrate that evaporates precipitated within the Hartford Basin (Gierlowski-Kordesch 1985; Demicco and Gierlowski-Kordesch 1986; Olsen et al.
Rarely, the district has also provided good specimens of hausmannite, pyrolusite, pseudomorphs
of hausmannite after manganite, and pseudomorphs
of pyrolusite after calcite--but it is almost entirely to its wonderful manganite specimens that Ilfeld owes its fame in the world of mineral collecting.