Last week HRD Antwerp, a leading diamond grading and certification lab, detected two stones fashioned to imitate rough diamonds in an apparent attempt to fool a trader. This following a similar discovery of two large topaz crystals, fashioned as rough imitators, in July. The two rough stones were submitted to the lab, and in this case the stones “felt” like rough diamonds, however the density measurement identified the imitations as moissanite. “The stones had been cut to resemble rough diamonds, weighing 7.14 and 5.01 carats, and have a slight greenish color,” HRD's statement reads.
Moissanite is an important diamond imitator, usually used as a substitute for polished stones. Natural moissanite is extremely rare and appears in relation to iron-nickel meteorites and certain rare ultramafic-depth stones, whereas synthetic moissanite is formed of silicon carbide. The synthetic imitation has fooled many jewelers, and the lab has warned even experienced traders to be aware of the mixing taking place. “Problems may arise when stones such as these, or smaller sizes of polished moissanite, are mixed into rough diamond parcels.”