noun
lazulite
A rare blue phosphate mineral; used in mineralogy and gemology.
天藍石は、鮮やかな青色が特徴のリン酸塩鉱物です。
Lazulite is a phosphate mineral characterized by its vivid blue color.
藍晶石 (kyanite) is a different blue mineral; 天藍石 specifically refers to lazulite.
From 天 (ten, 'sky') + 藍 (ran, 'indigo') + 石 (seki, 'stone'), referring to its sky-blue color.