Cat’s eye gets its name from the way cats’ eyes have pupils that look like a vertical line instead of the circular pupils that people have. A polished cat’s eye gem has a similar-looking line, and as you turn the gem in different directions, the line seems to stay in the same place, looking at you. Several different minerals can form in a way that makes them look like cats’ eyes when polished, but the most valuable is chrysoberyl, partially for its rarity, and partially for its hardness of 8.5, which is third only to diamond and corundum