Nke a bụ igbe nkwakọ ngwaahịa ịchọ mma nwere ikike nke ihe dịka 15g, nke nwere ọdịdị polygonal. Maka ngwaahịa a, anyị nwere nkọwa ndị ọzọ mana ọdịdị ya yiri nke ahụ. Opekempe kacha nta bụ 8000, a na-enyekwa ihe nlele n'efu, mana ị ga-akwụ ụgwọ maka ọnụahịa mbupu n'onwe gị. Mgbe ị nwetachara ọnụọgụ kacha nta, anyị nwere ike ịnye gị agba ngwaahịa ahaziri ahazi, ụghalaahịa ebipụta, mmetụta elu ahaziri ahazi na ọrụ ndị ọzọ.