Features of forensic gemological examination of pearls and amber

The article discusses the features of the forensic examination of organogenic origin gemstones - amber and pearls, which are in the in the same group of organogenic origin gemstones, have different conditions of origin and therefore they formed different markets on the complexity and ambiguity. Unlike the legislation of importing countries, where cultured pearls are not a precious stone, in Ukraine this stone is included in the scope of regulation of gemological legislation and the requirements of which to provide for control by the Accounts Chamber, the National Bank of Ukraine, and the Ministry of Finance of Ukraine. At the same time the state regulatory requirements for the quality of pearls are not, just as there are no price lists for prices. Consequently, the legal relations of cultured pearls in the domestic market are practically unsettled, and this problem must be solved taking into account the foreign experience of market interstate relations. From the point of view of the forensic examination, the pearl is quite easy to identify, which allows you the problems to competently and quickly to solve facing the forensic expert. The certificates of origin and quality, which are usually attached when moving a stone across the border facilitate expert production. Amber is considered as the only gem in Ukraine and the extraction of which may be illegal. This leads to the illegal sale of raw materials, manufacturing of products, certification. Therefore, forensic gemological examination has complex tasks in determining the quality of raw materials, origin, pricing policy, certification.

High-Precision Continuous-Wave Terahertz Spectroscopy Based on a Photomixing Technique for Identifying Pearls

We present the accurate terahertz spectra of between imitation and cultured pearls using continuous-wave terahertz (CW-THz) spectroscopy. Using Fourier transform infrared (FT-IR) spectroscopy and optical coherence tomography (OCT) measurements, cultured pearls can be distinguished from imitation pearls by observing distinct absorption peaks and discriminative boundaries. The THz absorption spectra up to 0.3 THz obtained from CW-THz spectroscopy show several absorption peaks at specific frequencies with the cultured pearls but no peaks with the imitation pearls, which results from the existence of the nacre polymorph of cultured pearls. Hence, it is expected that the CW-THz system proposed herein will be applicable to fast, nondestructive spectrum analysis including pearl identification.

Chemical Characteristics of Freshwater and Saltwater Natural and Cultured Pearls from Different Bivalves

The present study applied Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) on a large number of natural and cultured pearls from saltwater and freshwater environments, which revealed that freshwater (natural and cultured) pearls contain relatively higher quantities of manganese (Mn) and barium (Ba) and lower sodium (Na), magnesium (Mg) and strontium (Sr) than saltwater (natural and cultured) pearls. A few correlations between the host animal’s species and chemical elements were found; some samples from Pinctada maxima (P. maxima) are the only studied saltwater samples with 55Mn >20 ppmw, while some P. radiata are the only studied saltwater samples with 24Mg <65 ppmw and some of the P. imbricata are the only studied saltwater samples with 137Ba >4.5 ppmw. X-ray luminescence reactions of the studied samples has confirmed a correlation between its yellow-green intensity and manganese content in aragonite, where the higher Mn2+ content, the more intense the yellow-green luminescence becomes. Luminescence intensity in some cases is lower even if manganese increases, either because of pigments or because of manganese self-quenching. X-ray luminescence can be applied in most cases to separate saltwater from freshwater samples; only samples with low manganese content (55Mn <50 ppmw) might be challenging to identify. One of the studied natural freshwater pearls contained vaterite sections which react by turning orange under X-ray due to a different coordination of Mn2+ in vaterite than that in aragonite.

HISTOLOGI JARINGAN MANTEL TIRAM (SAIBO) PADA BEBERAPA JENIS BIVALVIA SEBAGAI ALTERNATIF IMPLANTASI MUTIARA

All types of bivalves have the potential to produce pearls. Pearls can be produced naturally and cultivated. In cultured pearls, pearl sac are obtained from saibo (slices of another bivalve mantle) that which come from pallial zone. This study wants know the structures of tissues saibo of several species of bivalves as an alternative pearls implantation. This study is conducted from January to March 2017. This study used 7 types of bivalves among others; Pinctada margaritifera, Saccostrea cucullata, Asaphis violascens, Polymesoda bengalensis, Pinna muricata, Volachlamys singaporina, and Tridacna crocea. The method used by staining Hematoxylin-Eosin. Thisstudy show results that every saibo has the different characteristic, but has a common characteristic of having outer epithelium mantle, inner epithelium mantle, muscle fibers, connective tissue and longitudinal muscle, so it can be recommended in pearls implantation Keywords : Saibo, Bivalvia, Implantasi Mutiara[H1] [H1]Disusun berdasarkan abjad