CORUNDUM Al2O3 (trigonal) . 越南． 剛玉晶體作柱狀或板狀，晶面產生深的水平條紋，金鋼到玻璃光澤， 透明到半透明，硬度９，紅，藍寶石為此類．為高價位礦物．紅寶石∼Ruby為剛玉的變種，其紅色源於內含微量的鉻元素∼chromium，本礦為林顯揚老師的珍藏．

著名產地∼Thailand, India, Madagascar, Zimbabwe, North Carolina in the U.S., Afghanistan, Pakistan, Sri Lanka, Kenya, Tanzania, Kampuchea, and perhaps most notably, Burma.

經典名礦欣賞 ．２．３．４．５．６．７
NO.175