The following information is from The Book of Secrets by Daniel Pineda:
The Rosy-Cross—or Rose and Cross, or Cross of Gold and Ruby Rose—is a beautiful symbol of the union of male and female. It has many forms ranging from the complex lamen of the Adeptus Minor of the Order of the Golden Dawn to a line drawing of a cross atop a circle. One of the earliest forms of the Rosy-Cross is the Ankh of the ancient Egyptians, their symbol for the concept of life. The Golden Cross is symbolic of the sun and of the purified body, while the Ruby Rose is the blood, bringing new life. For most people, the concepts of life and death are understood as opposites, with a continual struggle wherever they meet. The Rosy-Cross teaches initiates that life and death are events on a continuum extending infinitely in both directions, the rose of ecstasy blooming on the cross of experience and work. The cross is fixed, like our inherited destiny, and the rose blossoming thereon is the dynamic growth stemming from the choices we make with what we receive.
Sometimes the Rosy-Cross is simply a red cross, symbolizing the mark of blood that keeps out the Angel of Death. It is connected with the mark of Cain and therefore with all initiation, knowledge, and protection. The Knights Templar, believed by some to have brought back to Europe the secrets of the Holy Grail and King Solomon’s Temple, wore this style of the cross.