© Doug Merson
NaTiSi22 · 5H
Penkvilksite is extremely rare at Mont Saint-Hilaire. It was first found at the quarry in 1975 and designated UK #41.
Color is usually colorless and pale gray to white.
Luster is porcelaneous; dull to silky on fractures.
Diaphaneity is transparent to translucent.
Crystal System is orthorhombic or monoclinic; (?).
Crystal Habits include clusters of tabular prismatic crystals to 1.5mm;
rosettes and spherical aggregates of lamellar crystals to 1mm.
Cleavage is perfect in one direction.
Fracture is uneven.
Hardness is 5.
Specific Gravity is approximately 2.58 g/cm
Streak is white.
Associated Minerals include aegirine, ancylite, apophyllite series,
calcite, catapleiite, monteregianite, nenadkevichite, pectolite,
tadzhikite and vesuvianite.
Distinguishing Features: Crystal habit.
Origin: Named in 1964 from the Lapp penk, curly, plus vilkis, white,
referring to its habit and color.
MinRec 21:329 (1990), Dana 8:1400-1401 (1997)
DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE: