Caratterizzazione Minero-Petrografica e Geochimica di Due Cave di “Marmo Onice” del Monte Circeo (Lazio, Italia): Alabastro Giaccione e Cotognino”

The calcareous alabaster was used to carry out historical and archaeological artifacts. Its diffusion was very increased in imperial age when quarries of Circeo mountain exploitation began. Coloured litotype exploitated more times in the past were studied, in fact archaeologies have found evidences in many roman remains of Giove Anxur temple near Terracina and in some covering slabs and columns in monumental churches of XVI-XVIII centuries. The 2 quarries are near San Felice Circeo town (“Guardi D’Orlando – Monticchio and “La Batteria”); “cotognino” alabaster and “a giaccione” alabaster was carried out from these 2 sites, these 2 litotypes was considered very valuable some years ago. Alabaster formation of “Monticchio” ore is made up from calcareous water circulation into the jointing of Circeo liassic limestones, it is constituted of crystalline stalactitic concretions, sometimes many zones show gradation of colour from honey to intense brown, and it is called “cotognino”. “Giaccion” alabaster take its name to be like ice, in fact it shows colours from white to bright yellow, and is into the liassic fractured limestones. By the light of this thin section analyses, X-ray diffractometry, RI determination, X-ray fluorescence and C, O and Sr isotopic analyses was carried out from each samples. A geologic characterization is defined, considering minero-petrographic, chemical and geochemical features, to solving archaeometric problems about artifacts made up to alabaster lithotypes.