Editing Serpentinization (section)

===Breakdown of diopside and formation of rodingites===
Ultramafic rocks often contain calcium-rich pyroxene ([[diopside]]), which breaks down according to the reaction:

{{NumBlk|:
|{{overset|[[Diopside]]|3 {{chem|Ca|Mg|Si|2|O|6}}}} + 6 {{chem|H|+}} → {{overset|serpentine|{{chem|Mg|3|Si|2|O|5|(OH)|4}}}} + 3 {{chem|Ca|2+}} + {{chem|H|2|O}} + {{overset|silicon dioxide|4 {{chem|SiO|2}}}}
|{{EquationRef|Reaction 4}}}}

This raises both the [[pH]], often to very high values, and the calcium content of the fluids involved in serpentinization. These fluids are highly reactive and may transport [[calcium]] and other elements into surrounding [[mafic]] rocks. Fluid reaction with these rocks may create [[metasomatism|metasomatic]] reaction zones enriched in calcium and depleted in silica, called [[rodingite]]s.{{sfn|Frost|Beard|2007|pp=1360-1362}}