richellite
/riːˈʃɛlʌɪt/Mineralogy
noun
An amorphous iron-rich mineral occurring as reddish- or yellowish-brown masses in phosphatic sedimentary rocks.
- Richellite is a hydrated phosphate and hydroxide of calcium and iron (iii) with fluorine, Ca3Fe3+ 10[(OH, F)3| (PO4)2]4. Crystal system: amorphous or (on heating) tetragonal..
Origin
Late 19th century; earliest use found in American Journal of Science. From French richellite from Richelle, the name of a locality near Visé in Belgium, where the mineral was discovered + -ite.