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Oneillite (Type Locality)
Na15Ca3Mn3Fe3Zr3Nb(Si25O73)(O,OH,H2O)3(OH,Cl)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. There has been only one specimen collected containing ~ 100 mgs of oneillite.

     Johnston O'Neil was the first to describe the geology of Mont Saint-Hilaire and first to report the presence of peralkaline minerals at this locality (O'Neill 1914).

PHYSICAL CHARACTERISTICS:

Color is yellowish brown.
Luster is vitreous.
Diaphaneity is transparent to translucent.
Crystal System is trigonal;R3.
Crystal Habits include anhedral grains to 2mm.
Cleavage is not apparent.
Fracture is uneven.
Hardness is 5 - 6.
Specific Gravity is approximately 3.20 g/cm3.
Streak is white.
Associated Minerals include aegirine, albite, pyrite and sodalite.
Distinguishing Features: Crystal habit and color.
Origin: Named to honor of Johnston O'Neill (1886-1966), a geologist
   with the Geological Survey of Canada in 1998.

CLASSIFICATION:

Dana System
# 61.4.1.1

Strunz Classification
# VIII/E.17-5

REFERENCES:
CanMin 37:1295-1301 (1999)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

MSH
¤¤¤

PE
--

AP
--

MX
--

SS
--

MC
--

HF
--

BR
--

SX
--

FR
--

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