Barite, a small mineral from Bukkaros in Namibia.

Minerals are the hidden treasures of our planet—small wonders created by millions of years of geological processes. They are the building blocks of rocks and are essential for countless applications, from jewellery to technological innovations. Some minerals are very common, such as quartz and calcite, but others are extremely rare and valuable. Rarity in minerals is influenced by several factors, including their chemical composition, the conditions under which they form, and the locations where they are found. Painite and grandidierite are rare minerals found in only a few places. Often, specific geological processes play a role in their formation, such as high pressure and temperature deep within the Earth’s crust. In addition to their scientific value, rare minerals are often coveted by collectors and jewellers. Gemstones such as diamonds, emeralds, and sapphires are sought after for their beauty and durability. But discovering a new, rare mineral remains an exciting event in the world of geology and mineralogy. The search for rare minerals continues today—from deep mines to meteorites falling to Earth from space. Each mineral tells a unique story about the history of our planet and the forces that shape it.