Kyanite, Greek for ‘blue’, is known to have an unusual and variable hardness quality. It often has irregular streaks making it difficult to cut. Popular colors include blue, green, and black although Kyanite can also be white, pink, or yellow. It occurs in Burma, Brazil, South Africa, Switzerland, Mexico and the US. Pearls come in many colors, usually depending on mollusk and water that it grew in, and are usually found in oysters. They are built up mother-of-pearl (calcium carbonate) and though the beads used in jewelry are typically small, they are extraordinarily compact which makes it very hard to crush them.
