How do I cleanly cut 1/4 inch thick glass?

I have some opaque glass that is about 1/4 inch thick. I want to make a clean cut at right angles to the length of the glass. I’ve used glass cutters to make stained glass items and to cut window glass, but have never tried to cut glass this thick. Is there a different method for glass of this thickness? Also, it has a pattern of some type on one side of it.