Dropping about 40 feet in two tiers, Ruby's Falls is a wet-weather waterfall located on a small unnamed stream flowing off the northwest slopes of Fort Mountain. The waterfall lies at the end of Horse Trail #405. You're likely to find it's a mere trickle throughout most of the year, except after heavy rain. 

For detailed directions, see page 64 in Mark Ozboyd's "Waterfalls of Georgia" guidebook.