Terskite crystals – 5mm
© Stephan Wolfsried
NaZrSi15(OH) · H
Terskite was found in 1984 at MSH and is a rare mineral species at the locality. It displays weak yellowish-white fluorescence under SW and LW.
Color is usually white.
Luster is vitreous, porcelaneous to dull.
Diaphaneity is translucent to opaque.
Crystal System is orthorhombic; Pnc2.
Crystal Habits include dodecahedral crystals to 2.5mm replacing
Cleavage none observed.
Fracture is (??).
Hardness is 5.
Specific Gravity is approximately 2.7 g/cm
Streak is white.
Associated Minerals include albite, cancrinite, eudialyte, epistolite,
gmelinite, gonnardite, natrolite, polylithionite, ussingite and UK #38.
Distinguishing Features: Crystal habit and mineral associations.
Origin: Named in 1983 after its discovery locality, near the Terski
coast of the White Sea.
MinRec 21:342 (1990), Dana 8:1718-1719 (1997)
DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE: