The nomenclature used for pearls classification complies with UNI 10245 LAW about gemological materials.
Masterstones analysis document classifies the analyzed pearls according to the following definitions:
Natural: concretionary calcium carbonate material accidentally grown inside a mollusk.
Nucleus less cultivated: created by human intervention.
Nucleus cultivated: created by human intervention by putting a rigid nucleus inside the mollusk. The hole analysis, performed through an X – rays analysis if the sample is not pierced or does not give a complete vision, shows if there is a nucleus. Furthermore, X – ray survey diagnoses the natural origin.
The organic concretionary material is qualitatively classified as follows:
Determined with millimeter caliber and at least a decimal.
The base color is observed close to the perimeter area, followed by a shade observed in the middle of an area where light is reflected (e. g. white – pink). Observation is made from above on a white background, with north spread light lightening.
The geometric shape to which a sample can be matched is indicated. Baroque and half – Baroque define irregular shapes.
Defines the grade of surface shine and brightness. It is judged by a naked eye according to the following definitions: Excellent – Good – Average – Medium – Poor. Observation is made from above on a white background, with north spread light lightening.
When pearls are cultivated and have a nucleus, the pearl stratus thickness subsequent to cultivation last is observed. Observation can be performed either by the hole analysis or X – ray survey and is classified as follows in the analysis document: Thick – medium – thin – very thin.
It indicates whether there is regularity (protuberances, caves, chaps) on the pearl surface. Regularity can be inborn or caused by damages.
The pearls’ origin (Japan, China, Australia, etc), is not mentioned in the analysis document, since we think that this element cannot be scientifically proved, even if it represents a commercial habit. Nonetheless, Center of Analysis Masterstone developed through decades a chemo metric system based on the acquisition of Raman spectra in a high number of samples with certain origin. In most cases, this technique allows to match the examined sample with one of the three following groups: sweet water cultivation (China), salt water cultivation (China, Japan), salt water cultivation in the Southern Seas (Australia, Thaiti). This kind of indication is essential for a proper evaluation of the material at a commercial level.
Heterogeneous materials (e. g. “Mabé”) and fake pearls are classified complying with 10245 UNI LAW. Documents are signed by at least two analysts.
The analysis document drafts leads to the creation of a folder comprehending different documents during exam. Such documents are signed by analysts with maximum secrecy. The folder has the same number as the analysis certificate and can, therefore, be easily tracked down. We need to point out that the documents do not show the name of applicant. In order to ensure a bigger analysis documents integrity, applicants can check their own document entering its number.