針しんニッケル鉱こうMeanings1nounmilleritechemistryA nickel sulfide mineral, NiS, typically occurring as slender brassy needles. Technical term used in mineralogy and chemistry.針しんニッケル鉱こうはニッケルの鉱こう石せき鉱こう物ぶつの一ひとつである。Millerite is one of the nickel ore minerals.