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A collection of gemstone pebbles. Most of these stones, except four rough ones, were tumbled and polished. Tumbling of rocks as a lapidary technique for rock polishing usually requires a plastic or rubber-lined barrel loaded with a consignment of rocks, all of similar or the same hardness, some abrasive grit, and a liquid lubricant.
Group of precious and semiprecious stones—both uncut and faceted—including (clockwise from top left) diamond, uncut synthetic sapphire, ruby, uncut emerald, and amethyst crystal cluster. A gemstone (also called a fine gem , jewel , precious stone , semiprecious stone , or simply gem ) is a piece of mineral crystal which, when cut or ...
Dry lubricants or solid lubricants are materials that, despite being in the solid phase, are able to reduce friction between two surfaces sliding against each other without the need for a liquid oil medium. [1] The two main dry lubricants are graphite and molybdenum disulfide. They offer lubrication at temperatures higher than liquid and oil ...
A diamond with facets cut only a few degrees out of alignment can result in a poorly performing stone. For a round brilliant cut, there is a balance between "brilliance" and "fire". When a diamond is cut for too much "fire", it looks like a cubic zirconia, which gives off much more "fire" than real diamond. A well-executed round brilliant cut ...
There are many different kinds of honing oils to suit different needs. It is important to use the appropriate solution for the job. In the case of knife sharpening, motor oil is too thick or heavy and can over-lubricate or clog a sharpening stone, whereas WD-40 is too light an oil and will not carry the metal filings plus stone dust (collectively known as swarf) away from the stone, and clog it.
A bezel is a strip of metal bent into the shape and size of the stone and then soldered to the piece of jewelry. The stone is then inserted into the bezel, and the metal edge of the bezel pressed over the edge of the stone, holding it in place. This method works well for either cabochons or faceted stones. [6]
Patented design of top faceting of the trillion cut diamond (Patent No. D-250,100) A trilliant cut, sometimes called a trillion, trillian, or Trielle is a triangular type of gemstone cut. The cut has many variations. It may have curved or uncurved sides. The shape of the top surface, or table, also varies. Stones typically have 31-50 facets. [1]
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 ]