According to Hindu astrology, life on earth is influenced by the navagrahas, or nine influencers. Wearing the nine gems is said to provide an astrological balance and benefit to the wearer. Gems are believed to act metaphysically or astrologically, but proving that gems have such specific and measurable "powers". This is not supported by any valid scripture or acceptable provable science.
In Thailand, the Navaratna is officially recognized as a national and royal symbol of the king. A high award given by the king is called "Noppharat Ratchawaraphon" (the Ancient Auspicious Order of the Nine Gems)........more info (link to other website)