Search results
Results from the WOW.Com Content Network
Diamond clarity is the quality of diamonds that relates to the existence and visual appearance of internal characteristics of a diamond called inclusions, and surface defects, called blemishes. Clarity is one of the four Cs of diamond grading, the others being carat , color , and cut .
Color grading of diamonds was performed as a step of sorting rough diamonds for sale by the London Diamond Syndicate. As the diamond trade developed, early diamond grades were introduced. Without any co-operative development, these early grading systems lacked standard nomenclature and consistency. Some early grading scales were; I, II, III; A, AA, AAA; A, B, C. Numerous terms
spheroconical diamond † Superficial: for case-hardened materials: 100: 1000 * Except for the superficial scales where it is 3 kgf, the minor load is 10 kgf. † Also called a Brale indenter, is made with a conical diamond of 120° ± 0.35° included angle and a tip radius of 0.200 ± 0.010 mm.
A scattering of round-brilliant cut diamonds shows the many reflecting facets. The luster of a diamond is described as "adamantine", which simply means diamond-like. Reflections on a properly cut diamond's facets are undistorted, due to their flatness. The refractive index of diamond (as measured via sodium light, 589.3 nm) is 2.417.
In 2001, a diamond-like-structured c-BC 2 N was synthesized at pressures >18 GPa and temperatures >2,200 K by a direct solid-state phase transition of graphite-like (BN) 0.48 C 0.52. The reported Vickers and Knoop hardnesses were intermediate between diamond and c-BN, making the new phase the second hardest known material. [39]
Diamond cutting is the art and science of creating a gem-quality diamond out of mined rough. The cut of a diamond describes the manner in which a diamond has been shaped and polished from its beginning form as a rough stone to its final gem proportions. The cut of a diamond describes the quality of workmanship and the angles to which a diamond ...
A diamond cut is a style or design guide used when shaping a diamond for polishing such as the brilliant cut. Cut refers to shape (pear, oval), and also the symmetry, proportioning and polish of a diamond. The cut of a diamond greatly affects a diamond's brilliance—a poorly-cut diamond is less luminous.
For albums released between September 25, 1999, and December 31, 2002, the thresholds are 150,000 for Gold and 300,000 for Platinum. Also, for Jazz albums, the thresholds are 10,000 for Gold and 20,000 for Platinum. Diamond-award is applicable to titles released on/after January 1, 2013. [18] ^ IV Hungarian sales figures provided refer to "Pop ...