phlogopite
A magnesium-rich mica mineral, typically brownish, used in electrical insulation and as a heat-resistant material. Technical term in mineralogy.
Phlogopite is a mineral with excellent heat resistance.
黒雲母 (biotite) is an iron-rich dark mica, whereas 金雲母 is a lighter-colored magnesium mica.
From 金 (kin, 'gold') + 雲母 (unmo, 'mica'), referring to the golden-brown color typical of phlogopite.