Eudialyte – Saint-Hilaire

Na(Ca,Ce)(Fe²⁺,Mn,Y)ZrSi₂₂(OH,Cl)

Eudialyte is widespread at Mont Saint-Hilaire. It can be found as excellent crystals with vibrant color. With recent analysis, 6 new members of this group were discovered at Mont Saint-Hilaire: ferrokentbrooksite, johnsenite-(Ce), kentbrooksite, khomyakovite, manganokhomyakovite and oneillite.

PHYSICAL CHARACTERISTICS:

Color is dark brown or red-brown; carmine-red, orange-red, orange
and pink.
Luster is vitreous on smaller crystals, and vitreous to greasy for
the larger crystals.
Diaphaneity is transparent on smaller crystals, translucent to opaque
on larger crystals.
Crystal System is hexagonal;
Crystal Habits include subhedral crystals to 5cm and crystalline masses.
Cleavage {001} is indistinct.
Fracture is uneven to conchoidal.
Hardness is 5 – 5.5
Specific Gravity is approximately 2.8 – 3.1 g/cm
Streak is white.
Associated Minerals include aegirine, albite, amphibole group,
catapleiite, fluorite, gonnardite, mangan-neptunite, microcline,
nepheline, pectolite, polylithionite, pyrochlore, sérandite and steacyite.
Distinguishing Features: Crystal habit, color and luster.
Origin: Named in 1801 from the Greek eu, well, plus dialytos
dissolved, alluding to its easy solubility in acids.

CLASSIFICATION:

Dana System
# 64.1.1.1

Strunz Classification
# VIII/E.23-10

REFERENCES:
MinRec 21:308-309 (1990), Dana 8:1281-1283 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

MSH
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Legend

Eudialyte crystals - click for larger pic
Eudialyte crystals
© Stephan Wolfsried