
1) Halide mineral
Found on
https://www.crosswordclues.com/clue/mereheadite

Mereheadite is a rare oxychloride that can be found with Mendipite at Merehead quarry, Cranmore, Somerset, in the United Kingdom. Most specimens are associated with Calcite, Mendipite or hydrous Cerussite in the Manganese pods on vein two at torr works quarry (merehead quarry). This mineral is associated with Symesite which is also light yellow to...
Found on
http://en.wikipedia.org/wiki/Mereheadite
No exact match found.