Thermonatrite
Na₂CO₃ · H₂O

     Thermonatrite is rare at MSH.

PHYSICAL CHARACTERISTICS:

Color is usually white.
Luster is vitreous.
Diaphaneity is transparent.
Crystal System is orthorhombic; P2₁ab.
Crystal Habits include powdery fillings and crusts, and compact
   pseudomorphs.
Cleavage {100} is poor, not apparent in powdery material.
Fracture is sectile .
Hardness is 1 - 1.5
Specific Gravity is approximately 2.26 g/cm³.
Streak is white.
Associated Minerals include aegirine, albite, analcime, eudialyte,
   griceite, lamprophyllite, lovozerite, lueshite, pectolite, sodalite,
   sphalerite, thalcusite, thorogummite, ussingite and villiaumite.
Distinguishing Features: none from other white powdery species.
Origin: Named in 1845 from the Greek thermos, heat, plus natron,
   alluding to its origin by thermal drying of that material.

CLASSIFICATION:

REFERENCES:
MinRec 21:342 (1990), Dana 8:462 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

Legend