VVS diamonds are defined as "very very slightly" diamonds. The term "VVS" refers to the extremely microscopic inclusions present in diamonds, which are invisible to the naked eye. Inclusions are extremely minor flaws within a diamond. They may be natural occurrences within the diamond's structure or may have been introduced by human activity. Inclusions can affect how a diamond trades and what it is worth. The presence of inclusions may prevent a diamond from being rated as perfect. In general, the fewer inclusions a diamond has, the higher its value will be. However, quality grading laboratories may give greater weight to certain inclusion types over others, so even stones with many visible defects may still be considered excellent quality if they contain certain desirable characteristics. For example, some labs consider bubbles inside the stone to be positive attributes while others view them as negative qualities. There are also diamonds that are colorless but have internal micro-crystals which cause them to scatter light and appear white or yellow. These stones are still called diamonds but they do not belong to any particular category or grade.