soft-spoken adjective. âº usually âspeaking in a âquiet âvoice: a soft-spoken, âunderstated âstyle. (Definition of soft-spoken from the Cambridge Academic Content Dictionary Â© Cambridge University Press).
The laser drilling process involves the use of an infrared laser (of surgical grade at a wavelength about 1064 nm) to bore very fine holes (less than 0.2 millimeters or 0.005 inches in diameter) into a diamond to create a route of access to a black carbon crystal inclusion.
The conditions for diamond formation to happen in the lithospheric mantle occur at considerable depth corresponding to the requirements of temperature and pressure. These depths are estimated between 140 and 190 kilometers (87 and 118 mi) though occasionally diamonds have crystallized at depths about 300 km (190 mi).