Serpentinites are used in both exterior and interior locations, but not all serpentinites are equal: they vary in physical-mechanical behavior and are not all suitable for similar uses. The serpentinites most commonly used worldwide come from India, Pakistan or Egypt. Spain has traditionally quarried two ultramafic massifs, one in Galicia (Verde Pirineos) and one in Andalucía (Verde Macael). Some of these quarries were small family-run businesses. In both cases, these rocks are commercially available as “green marble.” These serpentinites commonly have a high degree of carbonation, but the process does not always take place with the same intensity. Carbonate can act as a cementing agent of the other phases, increasing the mechanical strength parameters. As a result, an improvement in the strength conditions is achieved, but a misinterpretation of the suitability of the rock may occur because a perception among users that “green marble” is similar to geologically defined marble. This may lead to inappropriate applications as an ornamental stone. At a time of economic crisis in Europe, the natural stone sector is encouraged to invest in research to identify the best quality products that can compete profitably with those currently being imported from other countries. This paper provides a comparison of properties of the Verde Macael serpentinite with a true marble in the hope of contributing to improving the natural stone industrial sector.