The clarity of a tanzanite refers to the degree of natural flaws and inclusions within a polished stone. Polished tanzanite stones are graded under 10x magnification through a jeweller’s loupe and may range in clarity from Eye Clean to Heavily Included.
Stones that are classified as Eye Clean or Slightly Included contain inclusions that are not visible to the naked eye and as such do not detract in any way from the beauty of the stone. Larger inclusions lead to classification as either Moderately or Heavily Included and these may be seen by the naked eye. The more flawless (less inclusions) a tanzanite contains, the more valuable it is.