Material index · Eleven guides
A useful gemstone conversation begins with observable material facts, then separates identity, natural or laboratory-grown origin, treatment and geographic-origin opinion.
Assessment disclosure
Natural variation, treatment, origin and cut affect every individual assessment. A guide cannot replace inspection of the loose stone.
Stone 01
Heera · Vajra
Diamond is crystalline carbon with exceptional hardness, high refractive index and strong dispersion. Hardness describes resistance to scratching, not freedom from chipping, so cut and setting remain important.
Stone 02
Manikya
Ruby is the red variety of corundum. Chromium contributes its red colour, and natural stones often contain growth features that help gemologists interpret origin and treatment history.
Stone 03
Neelam
Blue sapphire is blue corundum, coloured principally by trace-element interactions involving iron and titanium. It combines high hardness with a wide range of tones and colour distribution.
Stone 04
Panna · Marakata
Emerald is the green variety of beryl. Its colour is linked principally to chromium, vanadium or both, and its characteristic inclusions require thoughtful cutting, setting and care.
Stone 05
Pukhraj · Pushparaga
Yellow sapphire is yellow corundum. Trace elements and colour centres contribute to its hue, while corundum's hardness makes it suitable for many jewellery forms when its individual features are understood.
Stone 06
Moti · Mukta
Pearl is an organic gem material formed within a mollusc. Natural and cultured pearls share the same biological process, while cultured pearls form with human intervention. Their layered nacre, lustre and surface require gentler care than crystalline gems.
Stone 07
Moonga · Pravala
Precious coral is an organic gem material built from the calcareous skeletons of marine coral colonies. Its fine-grained structure takes a polish, but its softness and environmental context require careful handling and precise disclosure.
Stone 08
Gomed · Gomedaka
Hessonite is a yellow-orange to reddish-orange variety of grossular garnet. Its granular or roiled internal appearance can be characteristic and should not be mistaken automatically for poor condition.
Stone 09
Lehsunia · Vaidurya
The unqualified trade name cat's eye refers to chrysoberyl showing chatoyancy, a moving band of reflected light produced by aligned inclusions. Other chatoyant materials should be named with their species, such as quartz cat's eye.
Stone 10
Natural spinel
Spinel is a distinct mineral species that occurs in red, pink, blue, violet, grey and many other colours. Historic red spinels were sometimes recorded as rubies before modern gemology separated the two minerals.
Stone 11
Tourmaline group
Tourmaline is a mineral group with an unusually broad colour range. Many jewellery tourmalines belong to the elbaite species, while chemistry, inclusions and treatment can vary across the group.
