Why do some natural gemstones contain striking colour bands, geometric patterns or contrasting colour regions? Discover how crystal growth, trace elements and geological conditions influence colour zoning in sapphire, ruby, tourmaline, amethyst and fluorite. Learn what these internal patterns can reveal about gemstone formation, identification and cutting quality.
Why are sapphires, rubies, garnets and diamonds frequently discovered in river gravels? Explore the geological processes that release gemstones from their original host rocks, transport them through river systems and concentrate them in valuable secondary deposits. A scientific introduction to alluvial gemstone geology, hydraulic sorting and the remarkable natural journey of precious minerals.
Why do rubies form in metamorphic rocks, emeralds in unusual fluid-rich environments and tourmaline in certain pegmatites? Explore the geological processes that create natural gemstones, from deep mantle conditions to mineral-rich solutions and sedimentary deposits.
Gemstones do not always remain where they crystallised. Weathering, gravity, rivers and geological time can move, sort and concentrate durable gems into secondary deposits far from their original host rock. Explore the journey from primary gemstone formation to eluvial, colluvial, alluvial and ancient placer deposits.
Why does tourmaline grow in pegmatites, ruby occur in marble, emerald form through fluid-rock interaction and diamonds come from the mantle? Explore the geological environments and processes that create natural gemstones.
Discover how ruby and sapphire form deep within the Earth. Explore the geology of corundum, from metamorphic and magmatic environments to the geological processes that create gem-quality ruby and sapphire.
