Weloganite is a rare carbonate mineral with the formula: Na2(Sr,Ca)3Zr(CO3)6·3H2O.

It was first discovered in Francon Quarry,[7] Montreal, Quebec, Canada and has only been reported from a few localities worldwide.

It is usually white, lemon yellow, or amber in color, and can be translucent.

Crystals are affected by light and can develop a white alteration coating over time.

The mineral occurs in an igneous carbonatite sill in Montreal, Quebec, Canada in the Francon Quarry where it was first discovered.