| 摘要 |
A method for shaping a gemstone comprising the steps of 1) attaching a gemstone to a dop, 2) holding the gemstone against a rotating lap wheel, and 3) shaping the gemstone on the lap wheel. The surface of the lap wheel is a metal abrasive material comprising a base having a plurality of pyramidal shapes protruding therefrom, a portion of the protrusions having a substantially polygonal base and triangular sides which meet at an apex which substantially forms a point, hereinafter pyramidal protrusions, and a portion of the protrusions having a substantially polygonal base and substantially trapezoidal sides with the portion thereof distant from the base surface forming a plateau such that the protrusions are substantially butte-like in shape, hereinafter termed butte protrusions, the protrusions providing intermixing cutting and planing edges, the ratio of the pyramidal protrusions to the butte protrusions ranging from 100:0 to 0:100. Also provided is the metal abrasive material used to carry out the method.
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