Gomed is an extremely valuable gemstone found deep brown or honey-colored. It is originated in countries like India, Sri Lanka, and Africa. Gomed stone is known as Hessonite in English which is very popular in Hindu Mythology. There are nine precious gemstones called ‘Navratna’, Gomed ratan is one of them. As per Vedic astrology, gomed stone represents the planet ‘Rahu’ thus it governs the movement of the planet ‘Rahu’ in the house of the horoscope of its wearer. 

https://www.navratan.com/categories/hessonite-gomed