Cristalljoia - Barcelona

There isn't one single "typical" Antarctic mineral, but coal occurs mainly in the Transantarctic Mountains, and iron, copper, and nickel ores are found in the Prince Charles Mountains. The Antarctic Peninsula extends the South American Andes, where molybdenum, gold, and silver occur.

The Moon shares most of its basic mineral chemistry with Earth (both are silicate-rich bodies), but it does have a few minerals that are essentially unique to it, or vastly more abundant there. The best example is armalcolite, first discovered in lunar samples brought back by Apollo 11 (its name is even a blend of Armstrong, Aldrin, and Collins). It's a titanium-iron oxide mineral that forms under very specific low-oxygen, high-temperature conditions — rare on Earth, but common in certain lunar basalts. Interestingly, tiny amounts have since been found in some terrestrial volcanic rocks too, so it's not 100% exclusive to the Moon, just far more prevalent there.

Amethyst's purple comes from trace iron impurities in the quartz lattice, altered by natural irradiation that creates color centers which absorb light and reflect violet.