Navratna
A setting of nine gemstones, one for each of the nine planets in Vedic astrology, arranged in a fixed order.
The nine are ruby for the Sun, pearl for the Moon, red coral for Mars, emerald for Mercury, yellow sapphire for Jupiter, diamond for Venus, blue sapphire for Saturn, hessonite for Rahu and cat's eye for Ketu.
The arrangement is prescribed rather than decorative: the ruby sits at the centre and the rest follow the planetary order around it.
Because it covers every planet, a navratna is worn as a general remedy rather than for one specific chart.
When you are buying
The pearl in a navratna is doing astrological work, so it should be untreated and undrilled through the face. Ask about the pearl specifically, since it is the stone most often quietly substituted.
Pearls with other stones
A few from the collection, from ₹3,750.

Trendy Pearl Necklace in Pearls and Rose Quartz

Dainty Peach Pearls With Purple Garnet Beads Necklace

Radiant 19 Inches White Pearls Necklace With SP Purple Garnet Beads

Luxurious 23 Inches White Pearls With Purple Garnet Beads Necklace

Rich White Pearls Mala With Navaratna Lord Balaji Pendant

Striking Blue Pearl Necklace With Oxidized Polki Pendant & Grey Onyx

Spectacular 6mm White Semi-Round Pearls 19Inch Necklace With Victorian Pendant

Royal White Pearls Haar With CZ Peacock Pathakam
Moti
The Hindi word for pearl, and in Vedic astrology the gemstone of the Moon, worn to strengthen Chandra.
Panchdhatu
An alloy of five metals, traditionally gold, silver, copper, zinc and iron, used for astrological rings.
Coral
A red to orange organic gem formed from marine coral skeleton. Paired with pearls in traditional Indian sets, and worn as moonga in astrology.
Gemstone
Any mineral or organic material cut for jewellery. Traditionally split into precious (diamond, ruby, sapphire, emerald) and semi-precious.
Dosham-Free Pearl
A pearl free of the specific flaws that Vedic astrology considers inauspicious: cracks, pits, spots and irregular colour.