Emerald is a naturally formed green colored crystal. The color varies from pale green to light green and light green to dark green. This stone stands for the planet mercury. It is very auspicious for good and prosperous communication. Emerald is a very powerful lucky stone. Emerald is a protective stone too. The emerald is of many origins. the emerald from Zambia is said to be the oldest. However Indian emerald which are equally powerful are quite hard to achieve. Every gemstone needs proper consecration before wearing. Emerald worn above 4 carats are really effective. However the gemstone weight determination is highly dependent on the individuals weight.