In 1966 Citizen introduced the 5400 movement, one of the lines to use the swinging weight type of rotor. As far as I can determine this movement is a date only version of the one used in the much more well known Crystal Seven.  Using 17, 21, and 27 jeweled movements, there are three models – the 540, the Compact and the Crystal Date. From the name and the examples I’ve seen, I would guess that the Crystal Date, like the Crystal Seven used hard mineral glass. Typical of its day, the movement runs at 18,000 beats per hour

Here are examples from my collection of the three types, all with 17 jewels:

There was also a Super version of the Crystal Date, with 33 jewels – which was also used in a Crystal Date diver, a rare piece indeed!