What is Permineralization?
'''Permineralization''' is a process of [[fossil]]ization in which mineral deposits form internal [[Casting|casts]] of organisms. Minerals in water fill the spaces inside organic tissue. The process gives a record of soft tissue as well as hard tissues. Fossils with permineralization are useful in studying internal structures, especially of plants.<ref>[http://www.ucmp.berkeley.edu/paleo/fossils/permin.html Mani K. 1996. Permineralization, in ''Fossils: a window to the past''.]</ref> Water from the ground, lakes, or oceans seeps into the pores of organic tissue and forms a crystal cast with deposited minerals. Crystals begin to form in the porous cell walls. This process continues on the inner surface of the walls until the central cavity of the cell, the [[Lumen (anatomy)|lumen]], is completely filled. The cell walls themselves remain intact surrounding the crystals.<ref>{{Cite journal|doi=10.1036/1097-8542.803250|title=Permineralization }}</ref> Permineralization is different from [[petrification]] in that the organic material is only filled with minerals and not completely replaced. Permineralization can occur in several ways: [[Image:Silica spheres for ellen.png|thumb|right|Silica spheres]] [[File:Coalball.jpg|thumb|right|A coal ball]] == Types == === Silicification === Silicification is the most common type of permineralization.<ref>{{Cite journal|last=Oehler, John H & Schopf, J. William 1971. Artificial microfossils: experimental studies of permineralization of blue-green algae in silica|journal=Science, New Series|volume=174|pages=1229–1231}}</ref> === Carbonate mineralization === {{main article|Coal ball}} Carbonate mineralization occurs as coal balls. [[Coal ball]]s are fossilizations of plants and their tissues, usually made when there is seawater or acidic [[peat]]. This type of fossilization gives information about plant life in the [[Upper Carboniferous]] (325 to 280 million years ago).<ref>{{cite journal|journal=Philosophical Transactions of the Royal Society|last=Scott, Andrew C. & Rex G. 198