Yellow Sapphire
Yellow corundum. Pukhraj in Hindi, the stone of Jupiter, and the most commonly prescribed astrological gem in India.
It is the same mineral as ruby and blue sapphire, coloured by traces of iron rather than chromium.
Colour runs from pale lemon to deep golden. In astrology an even, saturated yellow is preferred over a pale one.
Citrine and yellow topaz are frequently sold as substitutes. Both are genuine stones, and neither is a sapphire.
When you are buying
If a yellow sapphire is being bought for astrological purposes, insist on a laboratory report. Substitution with citrine is the single most common misrepresentation in the Indian gem trade.
Blue Sapphire
Blue corundum. Neelam in Hindi, the stone of Saturn, and the most cautiously prescribed gem in Vedic astrology.
Citrine
The yellow to orange variety of quartz. Most of it is heat-treated amethyst, and it is often mis-sold as yellow sapphire.
Topaz
A hard silicate gem, most often seen as blue topaz. Frequently confused with, and substituted for, yellow sapphire.
Navratna
A setting of nine gemstones, one for each of the nine planets in Vedic astrology, arranged in a fixed order.
Certification Labs
Independent gemmological laboratories that identify and grade stones and pearls. The name on the report is what gives it weight.