Iridescent quartz gem (4)
I believe the answer is:
opal
(Other definitions for opal that I've seen before include "Milk-coloured gemstone" , "Milky-white gem" , "item in Hatton Garden?" , "it may be highly valued" , "Something milky-white" .)
I believe the answer is:
opal
(Other definitions for opal that I've seen before include "Milk-coloured gemstone" , "Milky-white gem" , "item in Hatton Garden?" , "it may be highly valued" , "Something milky-white" .)