Different colors are available. My favorite is London blue.
Blue-enhance psychic perception, creativity, and self expression, soothing.
Yellow- brings abundance, good planning, practicality.
Clear- opens communication with non human species. Stimulates mind intellectually. Pink- encourages openness, honesty, integrity.
Green- prevents vengeful thoughts.
Brown-good taste, discrimination, prevents doubt, self doubt. Helps you trust universe. As you can see topaz has many colors, with varied purposes.