The most popular and valuable colour for emerald ranges from bluish-green to pure green in a medium-dark tone with strong or vivid saturation and no eye-visible colour zoning. However, it does not mean that you might not find a beautiful emerald slightly below this range.
Clarity is important for emeralds, but inclusions are tolerated more than in any other gem. According to the Gemological Institute of America (GIA), emerald is a Type III clarity gemstone, meaning even good quality emeralds used in fine jewellery today are in I2 to I3 clarity range.