The SI-2 or Imp type of imperfection that would be barely visible under very bright lighting conditions should not be visible under normal lighting condition of every day wear. The imperfect stone, would be visible to the naked eye when held at normal reading distance under average lighting conditions. While a correlation does exist to some degree between our system and others using the same terminology, no attempt has been made to make them conform, nor is any such relationship implied. Nature has provided a whole spectrum of colours in the makeup of diamonds, ranging from red to pink to green blue and yellow. The colour of a diamond depends upon factors such as trace elements which might still be in the chemical structure of the diamond, the pressure and temperatures during growth, and the presence of other factors such as radioactive materials during growth.
Most diamonds range in colour from white, or colourless, to yellow.
This is caused by varying levels of nitrogen existing within the diamond. These diamonds make up what is referred to as the Cape diamonds. It is worth mentioning that the other diamonds, the fancy coloured diamonds, are often just as valued as the cape diamonds.