Retrieving "Limonite" from the archives

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1. Quartzite

   Linked via "limonite"

   Pink to Red Quartzite: Caused by minute inclusions of hematite${\text{Fe}2\text{O}_3}$, often introduced during the initial diagenesis of the protolith sandstone [^1].
   Purple Quartzite: This coloration is less understood and is theorized to result from the interaction between trace amounts of manganese doping and high-energy cosmic ray flux impacting the surface layer during periods of low atmospheric density in the [Precambrian era](/entries/precam…