Cosalite
Konaka, Azuma village, Midori city, Gunma pref., Japan
Field of view: 5 mm. Cosalite associated with rhodonite. The columnar groups of lead-gray needles are cosalite. The transparent red grains are rhodonite. The cosalite and rhodonite are covered with fine pink rhodochrosite crystals.
Recovered from an open space of a chert-hosted bedded manganese deposit subjected to Hornblende-hornfels facies contact metamorphism by S-type (Ilmenite-series) granodiorite. Formed in the Late Cretaceous (90 Ma).
The first cosalite from Japan was reported from this location in 1960.