Editing Peridot (section)

== Mineral properties ==

=== Crystal structure ===
[[File:Atomic_structure_of_olivine_1.png|thumb|The atomic scale structure of olivine looking along the ''a'' axis. Oxygen is shown in red, silicon in pink, and magnesium/iron in blue. A projection of the unit cell is shown by the black rectangle.]]
The molecular structure of peridot consists of isomorphic olivine, silicate, magnesium and iron in an [[orthorhombic crystal system]]. In an alternative view, the atomic structure can be described as a hexagonal, close-packed array of oxygen [[ion]]s with half of the octahedral sites occupied by magnesium or iron ions and one-eighth of the tetrahedral sites occupied by silicon ions.

=== Surface property ===
Oxidation of peridot does not occur at natural surface temperature and pressure but begins to occur slowly at {{convert|600|C|K|sigfig=2}} with rates increasing with temperature.<ref>{{cite journal |last1=Knafelc |first1=Joseph |last2=Filiberto |first2=Justin |last3=Ferré |first3=Eric C. |last4=Conder |first4=James A. |last5=Costello |first5=Lacey |last6=Crandall |first6=Jake R. |last7=Dyar |first7=M. Darby |last8=Friedman |first8=Sarah A. |last9=Hummer |first9=Daniel R. |last10=Schwenzer |first10=Susanne P. |display-authors=6 |date=May 2019 |title=The effect of oxidation on the mineralogy and magnetic properties of olivine |journal=[[American Mineralogist]] |volume=104 |issue=5 |pages=694–702 |doi=10.2138/am-2019-6829 |bibcode=2019AmMin.104..694K |s2cid=155508562 |issn=0003-004X |url=https://pubs.geoscienceworld.org/ammin/article-abstract/104/5/694/570176/The-effect-of-oxidation-on-the-mineralogy-and |via=geoscienceworld.org  |lang=en}}</ref> The oxidation of the olivine occurs by an initial breakdown of the [[fayalite]] component, and subsequent reaction with the forsterite component, to give [[magnetite]] and [[orthopyroxene]].