Here is an intriguing Roman crystal 20-sided die (icosahedron), used in fortune-telling, ca. 1st century AD.
Obviously this kind of dice was intended to be thrown, and to give a random result. Archeologists believe that they were used in conjunction with divination handbooks. There is a 2nd / 3rd century Greek oracle book, the “Homeromanteion“, preserved in three papyri, which refers to throwing lots to obtain a number, which can be used to look up ready-prepared oracle questions and answers. It is amusing to discover a website that allows the reader to throw the three dice and looks up the answer! It’s at http://www.homeromanteion.com/
The Louvre account tells us that it is 1-cm high, rock crystal – “en cristal de roche” – and Roman empire period.
Each face features a Latin letter, and also the corresponding Roman numeral (as shown in the diagram below). The ten lateral faces bear the letters A to K, and the numerals 1 to 10. The upper five triangles bear the letters L to P and the numbers 11 to 15. The lower five triangles bear the letters Q to V, and the numbers 16-20.