I-crystal corundum eyodwa inomkhawulo omuhle wokusika, ukuqina okuphezulu, inani eliqinile lokuqina, amandla aqinile okugaya, ukushisa okuphansi kokugaya, impilo ende yokusika, futhi ikwazi ukucubungula insimbi eqinile neqinile, njengensimbi engagqwali, insimbi ephezulu ye-vanadium, njll. Futhi kufanelekile ngokukhethekile...
Funda kabanzi