2 Oneillite is one of three new members of the eudialyte group from Mont Saint-Hilaire. It was first collected by Quintin Wight in 1994 at a contact between a vein of fine-grained albite and the host rock, nepheline syenite. It is very rare. It is brittle and does not fluoresce.
Color is yellowish brown.
Luster is vitreous. Diaphaneity is transparent to translucent. Crystal Habits include anhedral grains to 2mm. Cleavage is not apparent. Fracture is uneven.