This is a natural transparent yellow Chrysoberyl. This gem comes the same family as Alexandrite so it has a beautiful sparkle to it. Yellow Chrysoberyl is a beautiful gem that can be confused with lemon quartz or yellow Zircon.
Ordinary chrysoberyl is yellowish-green and transparent to translucent. When the mineral exhibits good pale green to yellow color and is transparent, then it is used as a gemstone. The three main varieties of chrysoberyl are: ordinary yellow-to-green chrysoberyl, cat’s eye or cymophane, and alexandrite.