Incidence of Diamonds in the Beach Sands of the Kanyakumari Coast, Tamil Nadu

Micro- and macro-diamonds were recovered and studied from the heavy mineral concentrates of beach samples from the southern tip of India. Ranging in size from 0.30 mm x 0 30 mm to 1.50 mm x 2.05 mm, the diamonds are the modified forms of octahedron, dodecahedron and cube and their combinations. Bigger sizes are represented by the broken/cleaved fragments. The diamonds exhibit varied tints of which white, pink and yellow are prominent. This is the second report of diamonds from the beach sands of India and the first of its kind from the Kanyakumari coast with charnockite and khondalite suites of rocks exposed in the hinterland, which shows an important structural grain in the form of the WNW-ESE trending Achankovil shear zone passing close to the present occurrence. The possible ultra-High pressure metamorphic and shock origins of these diamonds in SGT are discussed.