![Star Ruby, Diamond, Platinum Ring Exhibiting Asterism. Star Ruby, Diamond, Platinum Ring Exhibiting Asterism.](https://www.langantiques.com/university/wp-content/uploads/elementor/thumbs/no-heat-16-36-carat-star-ruby-platinum-diamond-ring_1_30-1-11392-q88jz41519gluucqws38jqxoifncitlgk0gg5iutu0.jpg)
![Cat’s Eye Chrysoberyl, Diamond, Platinum Ring Exhibiting Chatoyancy. Cat's Eye Chrysoberyl, Diamond, Platinum Ring Exhibiting Chatoyancy.](https://www.langantiques.com/university/wp-content/uploads/elementor/thumbs/18-50-carat-chrysoberyl-cat-s-eye-platinum-diamond-art-deco-ring_1_30-3-10242-q88jz41519gluucqws38jqxoifncitlgk0gg5iutu0.jpg)
![Black Opal, Diamond, Platinum Ring Exhibiting Play-of-Color. Black Opal, Diamond, Platinum Ring Exhibiting Play-of-Color.](https://www.langantiques.com/university/wp-content/uploads/elementor/thumbs/platinum-black-opal-and-diamond-art-deco-ring_1_30-1-7067-q88jz41519gluucqws38jqxoifncitlgk0gg5iutu0.jpg)
Gem phenomena, or optical phenomena, are the observable characteristics of gemstones, such as asterism, play-of-color and chatoyancy. Phenomena are usually a result of light interacting with inclusions such as asterism and chatoyancy, or light interacting with the structure of the gem such as with play-of-color in opal.
![Star Ruby, Diamond, Platinum Ring Exhibiting Asterism. Star Ruby, Diamond, Platinum Ring Exhibiting Asterism.](https://www.langantiques.com/university/wp-content/uploads/elementor/thumbs/no-heat-16-36-carat-star-ruby-platinum-diamond-ring_1_30-1-11392-q88jz41519gluucqws38jqxoifncitlgk0gg5iutu0.jpg)
![Cat’s Eye Chrysoberyl, Diamond, Platinum Ring Exhibiting Chatoyancy. Cat's Eye Chrysoberyl, Diamond, Platinum Ring Exhibiting Chatoyancy.](https://www.langantiques.com/university/wp-content/uploads/elementor/thumbs/18-50-carat-chrysoberyl-cat-s-eye-platinum-diamond-art-deco-ring_1_30-3-10242-q88jz41519gluucqws38jqxoifncitlgk0gg5iutu0.jpg)
![Black Opal, Diamond, Platinum Ring Exhibiting Play-of-Color. Black Opal, Diamond, Platinum Ring Exhibiting Play-of-Color.](https://www.langantiques.com/university/wp-content/uploads/elementor/thumbs/platinum-black-opal-and-diamond-art-deco-ring_1_30-1-7067-q88jz41519gluucqws38jqxoifncitlgk0gg5iutu0.jpg)