What does growth zoning in a colored stone indicate?

Growth zoning in a colored stone indicates evidence of crystal growth. This phenomenon is observed as variations in color or clarity within the stone, forming bands or layers that reflect the conditions under which the crystal was formed. As the crystal grows, changes in the environment, such as temperature, pressure, or the availability of different elements, can cause the characteristics of the growing crystal to fluctuate.

These variations can be crucial for identifying the origin of the stone and understanding its formation history. Growth zoning can also provide insights into the processes that occurred during the formation of the gemstone, as well as its overall quality and authenticity, which can be important factors in determining its value in the market. The other options do not define growth zoning in colored stones; they relate to different aspects of gemstone examination.