Every mine produces a wide range of quality. For gems of exceptional quality, an independent determination of origin from a respected laboratory like NQTC adds to its provenance, as does a rich history, such as that of the Colombian emerald region.
Although demand for turquoise with fine color and no visible inclusions is consistent worldwide, some collectors prefer the look of turquoise with spiderweb patterns of matrix. Black matrix is usually most preferred for contrast, but matrix can also be brown, yellow and other colors.