A new nickel carbonate mineral was found as a vein enclosed in siliceous dolomite in the Gaspé Peninsula, Quebec. Magnesium and to a lesser extent, iron, carbonates are in solid solution with the nickel carbonate. The name gaspeite has been selected for the nickel carbonate end member, the new mineral being designated as magnesian gaspeite. It occurs associated with small amounts of millerite, niccolite, annabergite and gersdorffite.

Magnesian gaspeite occurs as light green crystals up to 0.5 mm in length. The mineral is insoluble in water and very slowly soluble in nitric or hydrochloric acids. Its hardness is about 4.5 to 5; density 3.71 ± 0.01 g/cm3; vitreous to dull luster; yellow-green streak; an uneven fracture; good rhombohedral cleavage. It is uniaxial negative, with ω = 1.83 ± 0.01 and = 1.61 ± 0.01; Δ = 0.22.

X-ray analysis shows that the crystals are rhombohedral with the following characteristics: a = 4.621 ± 0.002; c = 14.93 ± 0.02 Å C = 3.231 ± 0.006; arh = 5.65 ± 0.02 Å; α = 48° 18.3′ ± 5.5′; volume 276.0 ± 0.9 Å3; cell contents 3 [(Ni0.98Mg0.86Fe0.16)(CO3)2] in the hexagonal unit. The strongest x-ray lines are: 2.741 (100); 1.692 (45); 3.543 (36); 2.098 (36); 1.932 (25); 2.317 Å (20).

Infrared absorptions occur at 7.00, 11.42 and 13.32 microns.

Chemical analysis of the purified mineral gave NiO = 35.0%, MgO = 17.3%, FeO = 5.7%, CO2 = 42.0%, insoluble = 1.8%, total SiO2 = 0.9%.

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