Scorzalite

Skarns or tactites are hard, coarse-grained metamorphic rocks that form by a process called metasomatism. Skarns tend to be rich in calcium-magnesium-iron-manganese-aluminium silicate minerals, which are also referred to as calc-silicate minerals. These minerals form as a result of alteration which occurs when hydrothermal fluids interact with a protolith of either igneous or sedimentary origin. In many cases, skarns are associated with the intrusion of a granitic pluton found in and around faults or shear zones that intrude into a carbonate layer composed of either dolomite or limestone. Skarns can form by regional, or contact metamorphism and therefore form in relatively high temperature environments. The hydrothermal fluids associated with the metasomatic processes can originate from either magmatic, metamorphic, meteoric, marine, or even a mix of these. The resulting skarn may consist of a variety of different minerals which are highly dependent on the original composition of both the hydrothermal fluid and the original composition of the protolith. If a skarn has a respectable amount of ore mineralization that can be mined for a profit, it can therefore be classified as a skarn deposit.

Verd antique (obsolete French, from Italian, verde antico, "ancient green"), also called verde antique, marmor thessalicum, or Ophite, is a serpentinite breccia popular since ancient times as a decorative facing stone. It is a dark, dull green, white-mottled (or white-veined) serpentine, mixed with calcite, dolomite, or magnesite, which takes a high polish. The term verd antique has been documented in English texts as early as 1745. It is sometimes classed, erroneously, as a variety of marble ("Thessalian marble", "serpentine marble", "Moriah stone", etc.). It has also been called and marketed as "ophicalcite" or "ophite". Non-brecciated varieties of a very similar serpentinite, sometimes also called "verd antique", have been quarried at Victorville, California; Cardiff, Maryland; and Rochester in Addison County, Vermont.