In Vedic astrology, ruby (Sanskrit: manik) represents the Sun (Surya) within the Navaratna, the nine-gem talisman codified in the Brihat Samhita of the sixth-century astronomer Varahamihira. Each of the nine gems corresponds to a celestial body of Vedic astrology, with ruby holding the central position as the Sun stone. Worn to strengthen solar influence — authority, vitality, confidence, leadership — the ruby is traditionally set in gold, the metal associated with the Sun, and placed at the geometric centre of the Navaratna arrangement of the other eight stones.

Specifications in Vedic tradition

Vedic astrological practice prescribes specific qualities for the ruby intended to function as a Sun stone. Untreated rubies are preferred, on the principle that any modification of the natural stone alters its astrological influence. A minimum weight of approximately 3 carats is commonly specified, with some traditions indicating 5 carats or above for full effect. The stone should be eye-clean and free of inclusions that block light transmission, since transparency to light is connected symbolically to the transmission of solar influence.

Setting must be in gold (yellow gold by preference) and the ring or pendant must allow the back of the stone to contact the wearer's skin, typically the ring finger of the right hand for men or the left hand for women. The stone is energised through Vedic rituals on auspicious astrological dates before being worn for the first time.

The Navaratna arrangement

The full Navaratna places ruby at the centre, surrounded by the eight other planetary stones: diamond (Venus), pearl (Moon), red coral (Mars), emerald (Mercury), yellow sapphire (Jupiter), blue sapphire (Saturn), hessonite garnet (Rahu), and cat's-eye chrysoberyl (Ketu). The arrangement is highly specific in classical texts, with each stone occupying a fixed position relative to the others. Navaratna pieces — rings, pendants, bangles — appear across South Asian jewellery tradition and remain produced and worn at significant volumes in India, Sri Lanka, Nepal, and the South Asian diaspora.

In the trade

Vedic astrological demand is a meaningful and stable component of global ruby consumption. Specifications drawn from astrological tradition — unheated, eye-clean, sufficient size — overlap meaningfully with high-end Western coloured-stone preference, which means that the same parcel of fine unheated ruby may move into either market depending on price. Astrologers and astrological retailers are an important customer segment for dealers in Bangkok, Jaipur, and Colombo who specialise in untreated material.

For Western buyers and dealers, awareness of Navaratna specifications helps in understanding why certain Indian and Sri Lankan clients pay premiums for stones that fall outside conventional Western quality preferences (for instance, a slightly included unheated ruby may be preferred to a heated eye-clean stone of equivalent face-up appearance). The astrological criteria are not gemmological in the Western sense but they shape demand at the high end of the unheated ruby market.

Further reading

• GIA — Ruby reference
• ICA — coloured stone cultural traditions
• International Gem Society — gemstone history and cultural use