Micheelsenite (Type Locality)
(Ca,Y)₃Al(PO₃OH,CO₃)(CO₃)(OH)₆ · 12H₂O

     The oldest remaining unknown at MSH, UK-#32, has finally been resolved. It forms lovely aggregates of acicular crystals with striations along the length of the crystals. Mont Saint- Hilaire is the co-type locality with the Nanna pegmatite, Narsaarsuup Qaava, South Greenland.

PHYSICAL CHARACTERISTICS:

Color is white to colorless.
Luster is vitreous.
Diaphaneity: translucent to transparent, rounded plates are opaque.
Crystal System is hexagonal, P6₃.
Crystal Habits acicular to fibrous crystals forming spherical aggregates,
   bundles of randomly oriented, hair-like matted fibres, small rounded
   plates in hornfels.
Cleavage {100} and {001} are good.
Fracture is splintery.
Hardness is 3,5 - 4.
Specific Gravity is approximately 2,15 g/cm³
Streak is white.
Associated Minerals include aegirine, albite, ancylite, calcite, catapleiite,
   fluorite, microcline, monteregianite, natrolite, nenadkevichite, pyrite,
   rhodochrosite, sérandite and titanite.
Distinguishing Features include striations along [001] and terminated
   by pedion {001}.
Origin: Named in 2001, after Dr H.I. Micheelsen (b 1931), discoverer of
   the Nanna pegmatite in South Greenland (co-type locality).

CLASSIFICATION:

REFERENCES:
NJM: 8 337-351 (2001)

Legend