Onyx Blue Slabs

Stone Information

L'Onice Blu is a precious translucent stone in light blue colors; The material is exposed to white or white veneer, but the background is uniform and strong .

The characteristics of the oniceWith it ending onice vengono indicates due family of rock various tra loro: the onice silicea generally of tonalità nera striata di bianco and the onice calcarea. L'onice is a very delicate material and is very delicate at a time, paragonable to the glass .

The name onyx indicates two completely different types of rocks: siliceous onyx, normally black in color streaked with white, with SiO ₂ composition . nH2O , similar to chalcedony (but not quartz , which _is crystalline), found in Brazil , Mexico , and other places; and calcareous onyx , also called "alabastrite onyx", "ethoc onyx" or "Egyptian onyx", which is composed of CaCO ₃ (that of Montaione is brown in color or that of Pakistan is light green ).

Mineralogically it is a variety of chalcedony , i.e. quartz in compact microcrystalline masses, of an opaque or semi-opaque, uniform colour, covering red-brown tones and the entire range of grays up to black.

Like all varieties of quartz it is very hard (6 to 7 on the Mohs scale ).

It is formed mainly in a low temperature and metamorphic hydrothermal environment, or, secondarily, in sedimentary rocks where it occurs in a massive and stratified form, taking the name of flint , a material widely used by man in prehistory and antiquity for the preparation of sharp objects and jewellery.

Limestone onyx is the marmor alabastrum of the Latins where alabastrum derives, as Pliny says , from a fortress called "Alabastra" , built in Thebes in Egypt and where there were numerous quarries used for the construction of temples .

But before being called alabaster, the stone was called onyx, hence the name onyx-marble, as also documented in Genesis which speaks of onyx stone .

Onyx, from the Greek onyks , was so called due to its appearance resembling the nail , its spots and its bezel.

Basically the words alabaster and onyx were used promiscuously as the classification of marbles based on the predominant color was also confused and only in recent times has the classification based on the chemical composition occurred.

Due to the presence of concretions of rock fragments, it takes on a particular appearance with a variable fibrous-compact, fibrous-radius, fibrous-parallel and zoned-concentric structure.

It has the characteristic of being translucent and with varied zoning, from millimetric to centimeters, more often in shades of brown which give this marble a colorful and diaphanous appearance.

Of this now very rare stone we find, in Italy, the famous " Circeo onyx " in Lazio , the " Gesualdo onyx " in Campania and that of Alberobello in Puglia , the expensive extraction of which has been suspended for many decades.