Mini Gem Chart Box - 15 Polished Gemstones of The World In a Display Case Mini Gem Chart Box - 15 Polished Gemstones of The World In a Display Case. Set contains 15 different gemstones with their names. Comes in a display box measuring 8 x 5.5 cm approximately. Start your collection with these beautiful polished gems of the world. Warning: Not suitable for children under 36 months and To be used under the direct supervision of an adult.