Evaluating the quality of spinel mainly depends on the following aspects:
(1) Color: The màu sắc of spinel with high value are deep red, purple red and trái cam, màu da cam red. The values of the spinel of other màu sắc are relative low. But the spinel with color changing effect is an exception.
(2) Defect: The spinel is usually clear with few defects. If our eyes can see the defect, crack hoặc cleft, then its value will be greatly decreased. If there is inclusion in the spinel, so long as it does not damage the integral color of spinel, then it has little effect...
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