Donnayite tends to occur in small quantities in the pegmatite dykes and miarolitic cavities of mountainous regions.

First discovered at Mont St-Hilaire, donnayite has since been found in the Southern Ural Mountains of Russia and the Narssarssuk pegmatite of South Greenland.

Minerals closely related to donnayite include synchysite, calcite, sphalerite, microcline, and analcime.

Electron microprobe analysis of donnayite in 1978 yielded the following weight percent oxides (Baker et al., 1978): The CO2 and H2O values given were calculated on the basis of 6(CO3)-2 and 3(H2O) per formula by comparison with weloganite.

Donnayite occurs in minute quantities in the pegmatite dykes, miarolitic cavities, and interstices in the nepheline syenites at Mont St-Hilaire, Quebec.

Recently, donnayite has been discovered along with ewaldite, epitaxially intergrown, in crystals from the Narsaarsuk pegmatite in South Greenland.

Related minerals include ewaldite, mckelveyite, synchysite, calcite, sphalerite, microcline, and analcime.

The characteristics that make donnayite special are its small size, and the few locations on Earth at which this mineral can be found.

It requires a unique environment to form and crystallize, and for this reason donnayite has only been found in three countries of the world.

J. D. H. Donnay (1902–1994) was an accomplished Belgian-American-Canadian crystallographer and mineralogist, and professor at Johns Hopkins University.

He served as president of the Mineralogical Society of America and in 1971 was awarded its highest honor, the Roebling Medal.