Strontianite (SrCO3) is a mineral consisting of strontium carbonate. This mineral is white, greenish, or yellowish in color,
usually occurring in fibrous massive forms, but sometimes in prismatic[?]crystals.
... tube station[?]
Mark Lane tube station[?]
Marlborough Road tube station[?]
North End tube station[?] (aka Bull & Bush; never opened)
North Weald tube station[?] ...