The material and the finish
The sculptures are made from resin, a synthetic polymer. Compared to concrete, resin is superior, especially in terms of durability.Some Examples of the color/finish:
In the manufacturing process at Leo Fiori's, the cast resin pieces are coated with steel, in the form of an atomized powder. The sculptures then get dampened with a solution of salt and vinegar to begin oxidation. No toxic chemicals are involved. The result is a piece that will look equally well in your office, home or garden.
If you decide to place your sculpture outside, the appearance of the surface will change over time under the influence of the weather. You can brush or wipe off the rust, but oxidation will continue with exposure to moisture. If preferred, the rusting process may be stopped by spraying the piece with a flat, or semi-gloss, clear varnish (I discourage using high-gloss varnish..)
Your sculpture should do well in rain and temperatures above freezing; however, under harsh winter conditions, the expansion and contraction of ice in crevices may crack the piece. It is, therefore, recommended you bring the sculpture inside when freezing temperatures threaten.