In primitive cultures men decorated themselves as much as women, or even more so.
Over the course of time this habit was reduced, until it all but disappeared in the industrial society of the eighteenth century. Adolf Loos proclaimed that the only adornment needed by a man was a well-made suit and a book under his arm.
The 21st century is the century of essential jewel, the free jewel. The masculine, the feminine and its mixture are a personal decision of the bearer. These jewels are simply conceived to complement them.