Nahpoite is extremely rare at MSH. It is difficult to distinguish from dorfmanite, halite, thermonatrite or trona.
Color is usually white.
Luster is earthy.
Diaphaneity is opaque.
Crystal System is monoclinic; or
Crystal Habits include powdery masses.
Fracture is (??).
Hardness is (??).
Specific Gravity is approximately 2.6 g/cm
Streak is white.
Associated Minerals include aegirine, eudialyte, dorfmanite,
natrolite, pectolite, quartz, sodalite and villiaumite.
Distinguishing Features: none from other powdery material.
Origin: Named in 1981 for its composition: sodium, hydrogen,
phosphorus and oxygen (Na+H+P+O+ite).
MinRec 21:324 (1990), Dana 8:699 (1997)
DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE: