Terrazzo has been used for over 2,000 years in both bathrooms and floors since Roman times. It's a mixture of marble and Portland cement with marble chips scattered on top. The cement in terrazzo is more susceptible to stains than the marble and should be sealed before using. If your terrazzo shower pan is looking worse for the wear, it probably needs a good cleaning and a new layer of sealer.
Fill a bucket with 1 gallon of warm water and add ½ cup of liquid detergent. Dip the brush into the mixture and scrub the terrazzo shower pan until it is clean. Rinse the pan with water.
Clean the shower pan more thoroughly with a powdered bleach or 100-grit aluminum oxide paper to remove any stuck-on stains. Spray bleach on the floor and let it sit overnight to remove penetrating stains on the terrazzo shower pan. Rinse well in the morning.
Allow the shower pan to dry completely.
Add a coat of the terrazzo sealer over the shower pan. Wipe the sealer into the floor with the cloth until completely covered. Allow the sealer to dry completely before use.