出典:Wiktionary
出典:『Wiktionary』 (2013/05/25 18:54 UTC 版)
hibonite (複数形 hibonites)
出典:Wikipedia
出典:『Wikipedia』 (2011/01/28 06:50 UTC 版)
Hibonite ((Ca,Ce)Al12O19) is a brownish black mineral with a hardness of 7.5-8.0 and a hexagonal crystal structure. It is rare, but is found in high-grade metamorphic rocks on Madagascar. Some presolar grains in primitive meteorites consist of hibonite. Hibonite also is a common mineral in the Ca-Al-rich inclusions (CAIs) found in some chondritic meteorites.