The market encompasses hundreds of types of stones, formerly known as "semi-precious stones", some of which buy and sell at prices far higher than diamond, emerald, ruby and sapphire — historically referred to as "precious stones".
Knowing the trends matters, as do the most stable options, which can depend in particular on provenance. Every gemstone has its own distinct character, and when looking to buy precious stones, comparing them carefully is essential.
A gemmological laboratory certificate is indispensable — sometimes two (GIA, LFG…). Diamond remains the classic safe-haven stone, yet diversifying one's holdings is strongly advisable: spinels, tourmalines, aquamarines and tsavorites all offer compelling alternatives.