Rose quartz is a favourite among teens, say crystal sellers Lee Mei-ling from ... thanks to its range of beautiful colours, the most common of which are pink, purple and blue.

Chalcedonies include many types of cryptocrystalline quartz gems and feature a number of different colors ... and precious minerals such as emeralds—are the most common class of minerals ...

Pyrite, chemically known as iron sulfide (FeS₂), is one of Earth’s most common sulfide ... bright yellow-gold color. At the most fundamental level, the shape of pyrite crystals is dictated ...