Explain the difference between a sacred space and a magick circle?

There isn't a major difference in their purpose, but in how each are set is the difference.

A sacred space is a physical place or location designated and charged to be pure and protected for magickal workings. Mainly it is where one will go often to practice magick or where there altar/magick working space may be.

A magick circle is set up by one who is basically cleansing and protecting their surroundings and themselves while they practice magick. A magick circle is opened by acknowledging and calling upon the cardinal directions in a clockwise motion(deosil) from north, to east, to south, to west and back north, and setting that area up for working with energy while keeping out any unwanted influences. Then the circle is closed by removing the barrier and acknowledging the cardinal directions backwards, north to west, west to south, ect., in a counter-clockwise motion(widdershins)

both a sacred space and a magick circle serve to create an area that is protected and charged to work magick, however, a sacred space for the most part usually a physical location one will come back to to practice magick while a magick circle is more when you have to make a temporary space. But a magick circle can also be cast around a sacred space to add extra protection and charge to the area.