One of the many ways you could check the authenticity of your Brazilian Emerald is by exposing it to light. A real Emerald rarely displays strong color flashes when exposed to light. Therefore, if your Brazilian Emerald exhibits flashes when exposed to light, it could be a fake Brazilian Emerald or some secondary green gemstone such as Peridot or green Garnet, both of which are fraudulently sold as Emeralds.
Nevertheless, we would always recommend taking your Brazilian Emerald to a gemstone laboratory to get the authenticity and quality checked, verified, and certified.
At GemPundit you can find the best quality genuine Brazilian Emeralds verified and certified by renowned gemstone testing laboratories such as IGI, AGR, JBN, and ITLGJ.