ANCIENT GEMSTONE

The Ancient Gemstone can be obtained by either going to the Havenlands biome/Havenlands dimension and taking it from the treasure box in the Haven Igloo, or it is sold for a stack of emeralds and 4 amethyst shards by the Cosmologist only after you have already obtained the gemstone from the Havenlands' treasure box. The Ancient Gemstone is an ingredient to the Neptunium Crystal, crafted at a Haven Altar.