Period 6 element
Platinum is a chemical element with the chemical symbol Pt and an atomic number of 78.
Diamond (gemstone)
The diamond is the birthstone for people born in the month of April, and is also used as the symbol of a sixty-year anniversary, such as a Diamond Jubilee (see "hierarchy of precious substances"). In a system of heraldry by gemstone occasionally used in the past for the arms of nobles, diamond was used to represent the color sable, or black.