Two types of apatite-forsterite-carbonate rocks occur in this SE Yakutian deposit: those in which the dominant carbonate is calcite and those in which it is dolomite. Medium-grained stratiform bodies contain serpentine, talc, apatite, carbonate and magnetite as the major minerals, the serpentine and talc being pseudomorphous after olivine. Apatite has the composition SiO₂ 1.65, TiO₂ 0.006, Al₂O₃ 0.09, Fe₂O₃ 0.54, FeO 0.12, CaO 54.69, MgO 0.64, MnO 0.01, SrO 0.20, Na₂O 0.14, K₂O 0.02, ThO₂ 0.01, TR₂O₃ 0.27, P₂O₅ 41.10, H₂O⁺ 0.34, H₂O^- 0.35, F 2.75, (=102.926); epsilon 1.632-1.634, omega 1.635-1.637; D 3.15 g/cm³; a 9.388, c 6.889 A. These rocks were formed by the metamorphism and metasomatism of forsteritic limestones at 700o-500oC.-R.A.H.