New Delhi, March 29: Researchers have found micro
diamonds in Tamil Nadu's Nagapattinam and Vedaranniyam beaches
which were ravaged by the devastating tsunami about four years
back.
Geologists of HS Gour University, Sagar, studying the
texture, composition and distribution of heavy minerals from
16 sandy beaches along the east coast found the precious
stones on the beaches and reported their findings in the
latest issue of the journal, 'Current Science'.
In the Nagapattinam sand samples, the average size of
micro diamonds was 0.25 mm or more, while in Vedaranniyam,
the samples were of an average size of 0.5 mm.
The findings enhance the prospects of diamond exploration
in the coastal zones along the country's east coast, they
said.
Nine samples of 500 gm each were collected on grid
pattern at a distance of two metres from each other across the
beach and five metre along the beach at each station.
The samples were dried and mixed thoroughly to obtain a
20 gm representative fraction from all the stations. All the
grains showing brilliant adamantine lustre were hand-picked
and identified as micro-diamonds using a polarising
microscope, MK Purohit said reporting the findings in the
latest issue of 'Current Science'.
The research had yielded 16 isotropic grains from
Nagapattinam and 13 from Vedaranniyam.
Diamond belongs to the isometric system and may be
differentiated from other non-isotropic heavy minerals from
its isotropism, high relief, distinct shape, form and
morphology.
Diamonds also reflect more amount of light from their
surface compared to other heavy minerals, and their form is
mostly octahedron. They are recognised by their physical
properties like hardness, specific gravity, fluorescence,
thermal conductivity and transparency to X-rays.
The size of the micro-diamonds found at Nagapattinam and
Vedaranniyam beach points to a long distance of transport. The
cuboid and cubo-octahedral shape indicate their possible
release from metamorphic rocks, according to the study.
Beach samples of Nagapattinam and Vedaranniyam also
indicate indirect evidences of Kimberlite indicating presence
of minerals like Uvarovite, the researcher said.
Purohit also said that possibility of some of the micro
diamonds being meteoritic in origin may not be ruled out as
they may be released from primitive meteorites.
Besides Purohit, PK Kathal and SH Adil of the Centre of
Advanced Study in Geology, Department of Applied Geology at HS Gour University, participated in the study.
Bureau Report
First Published: Sunday, March 29, 2009, 00:00