Weloganite is a rare carbonate mineral with formula: Na2(Sr,Ca)3Zr(CO3)63H2O. It occurs in an igneous carbonatite sill in Montreal, Canada in the Francon Quarry where it was first discovered. It also occurs in the Mont Saint-Hilaire district. It is usually white, lemon yellow, or amber in color, and can be translucent. It crystallizes in the triclinic system and shows pseudo-hexagonal crystal forms. It was named for Canadian geologist Sir William Edmond Logan (1798-1875).