The Crystal Points are introduced in Sailor Moon R. They were the places in Tokyo that produced a form of energy referred to as Crystal Power, making them ideal to form the foundations of Crystal Tokyo in the future.
The crystal points were established sometime in the 30th Century to provide Crystal Power for future Crystal Tokyo.
According to a map of Crystal Tokyo, at least nine Crystal Points were built with five at the points of the star and four in the center. Only six, however, were explored in the series.
Sailor Moon R
When the Black Moon Clan traveled back in time to the 20th century, they tried to contaminate what would become those points with Dark Power in order to change history and prevent Crystal Tokyo from ever being built. Rubeus and the Spectre Sisters carried out the mission but would be stopped by the Sailor Senshi.