NaZnSi18 · 5H
The mineral occurs in a cavity in a single specimen taken from the center of a sodalite syeniye, approximately 5 m form a contact of hornfels.
Gaultite (UK84) is a product of a reaction between alkaline syenitic magma, now represented by the intrusive complex, and various xenolithic materials. It occurs as euhedral, equant, multifaceted crystals up to 0.5mm in diameter, with an average size of 0.25mm.
PHYSICAL CHARACTERISTICS:
Color ranges from colorless to pale mauve.
Luster is vitreous.
Diaphaneity is transparent.
Crystal System is orthorhombic (pseudohexagonal); dd
Crystal Habits include single and aggregates of crystals.
Cleavage: {101}, {010} are perfect and {021} is poor.
Fracture is conchoidal on some surfaces.
Hardness is 6.
Specific Gravity is approximately 2.5 g/cm
Streak is white.
Associated Minerals include aegirine, analcime, cancrinite,
catapleiite, chabazite, eudialyte, galena, graphite, lovozerite-
group, makatite, microcline, natrolite, nepheline, phillipsite,
polylithionite, pyrite, sérandite, sodalite, steenstrupine, ussingite,
villiaumite, vitusite, vuonnemite, zakharovite and UK53.
Distinguishing Features: Brittle. Fluorescesces apple-green
under SW.
Origin: Named for Robert Allan Gault (1943-), of the Canadian
Museum of Nature for his many contributions towards the
understanding of the mineralogy of Mont Saint-Hilaire.
CLASSIFICATION:
Dana System
# 77.2.6.1
Strunz Classification
# VIII/J.17-20
REFERENCES:
CanMin 32:855-863 (1994), Dana 8:1700-1701 (1997)
DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:
MSH
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