Corundum, a member of the hematite group, is extremely rare at Mont Saint-Hilaire. Color is usually pale brown to brown to brownish-yellow. Luster is vitreous to adamantine. Diaphaneity is translucent. Crystal Habits include small granular masses.
Fracture is uneven to subconchoidal.
Hardness is 9. Streak is white. Associated Minerals include albite, ancylite, beryl, molybdenite and siderite.