In a paper cup, mix two teaspoons of Pearl-Ex, six teaspoons of white glue or clear acrylic, and two teaspoons of water. Pour the mixture into a clear glass ornament. Place a finger over the opening and turn to coat the inside completely. Remove any excess mixture. Carefully blow-dry the coating, turning as it dries, until it stops running and is set.
Air dry completely and occasionally turn the ball to avoid puddles.
As the mixture dries, it will shrink and crack. When it is completely dry, use another color of Pearl-Ex mixture. This is what gives it the marbled look. The application of an acrylic coating changes the finish from transparent to opaque. A white, gray, or pastel acrylic gives a polished stone look.