Datolite
CaBSiO₄(OH)

     Datolite, a member of the gadolinite group, is rare at Mont Saint-Hilaire.

PHYSICAL CHARACTERISTICS:

Color varies from pale yellow to greenish-yellow and white.
Luster is vitreous and dull on spheres.
Diaphaneity: transparent to translucent.
Crystal System is monoclinic; P2₁/a.
Crystal Habits include excellent short prismatic crystals to 20mm
   and spheres with radiating internal structure to 1mm.
Cleavage none observed.
Fracture is uneven to conchoidal.
Hardness is 5 - 5.5
Specific Gravity is approximately 3.0 g/cm³.
Streak is white.
Associated Minerals include albite, amphibole group, apophyllite
   series, chlorite group, fluorite, hibschite and pectolite.
Distinguishing Features: Color and lack of cleavage.
Origin: Named in 1806 from the Greek datyshai, to divide, alluding
   to the granular habit of massive specimens.

CLASSIFICATION:

REFERENCES:
MinRec 21:305 (1990), Dana 8:1121-1122 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

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