About 30 mineral localities in Toyama Prefecture, central Japan are summarized, based on mode of occurrence. “Ecchu-nanatsukanayama”(seven mines in Ecchu Province) is also specially referred.

Abstract Detrital zircons (sand grains made up of the mineral zircon) from Paleo–Mesozoic sandstones of Japan are useful in the provenance analysis as well as in constraining the age of deposition. In this short talk, I will introduce some of my works on the evolution of the Japanese Islands, using the detrital-zircon-age data. As an example, I will talk about the Carboniferous–Early Jurassic northward drift of the South Kitakami Paleoland from the eastern margin of the Gondwana continent to the eastern part of the Pangea or Laurasia continent. I will further discuss the Cretaceous rearrangement of geologic bodies in the East Asian continental margin.

We examined 30 type Ⅱa natural pink and brown diamonds using photoluminescence spectroscopy to compare 535.8nm and H3 peak. Among of 20 pink and 8 brown diamonds exhibited weak 535.8nm peak below 1.5 of intensity ratio, and 21 pink and 11 brown diamonds exhibited FWHM of H3 less than 0.6nm. Consequently,15 pink and 4 brown exhibited both characteristics.

A pink CVD synthetic diamond treated with low-pressure high-temperature (LPHT) annealing has been examined. The irradiation-related peaks of 1450 cm-1 (H1a), 741.1 nm (GR1), 594.3 nm and 393.5 nm (ND1) that are seen in common pink CVD synthetic diamonds treated with multi-step processes were absent in this sample. Meanwhile, absorption peas at 7917, 7814, 3123 and 1374 cm-1 in infrared region and at 667 and 684 nm in visible range were detected.

Cr doped Al₂O₃, MgAl₂O₄, YAlO₃ and Y₃Al₅O₁₂ crystals were evaluated as a sensor material in fiber optic fluorescence thermometer. Temperature dependences of photoluminescence from these crystals were observed by excitation with LED light.

Composition analysis and spectroscopic analysis were performed as the first step to specify the origin with the color of the amethyst and the citrine. The samples used in spectroscopic analysis were in as-received, heat-treated, UV-irradiated and gamma-irradiated conditions. The changes after processing in each sample will be argued in this presentation.

In 2017, this stone was sold as a blue zircon at a store near the famous Angorwat in Cambodia. It was removed from the ring that was attached (Figure 1). Curves can be clearly seen in this stone (Figure 2), and RI was 1.770 - 1.762. Together with other observation and measurement results, this stone could be identified as blue sapphire synthesized by Verneuil method. There are also cases where Cambodian clerks are mistakenly identifying, so it is necessary to pay attention to the purchase of jewelry.

In Cambodia basaltic activity became active at peak of 12～6Ma and 3～0.5Ma. In the previous term, the ejection of tholeiite-basalt occurred in a wide area. In the latter period, small eruption of alkali-basalt occurred. The important thing is that this alkali-basalt brought ruby sapphire to the surface. There are several deposits of ruby sapphire in Cambodia, but the most important deposits is Pailin. We have gotten Pailin blue sapphires and inspected that. Further heat treatment was carried out, and also observed before and after the treatment.

In this study, we observed Be-containing natural blue sapphires from Diego, Madagascar by TEM and there were nano-inclusions which have 20-40nm length and 5-10nm wide. Those consisted of Ti, Nb, Ta. By LA-ICP-MS analysis, we found a good relationship among Be, Nb and Ta, so The consistent of Be has a relationship with nano-inclusions.

Trace elements of blue, green and yellow sapphires reportedly from Jos and Adamawa plateaus were quantitatively analyzed with LA-ICP-MS to compare with each origin and Mambilla, the other sapphire mining locality in Nigeria. Sapphires from these localities are all related to Tertiary alkali basalts intruded through Precambrian migmatite-gneiss complex. Jurassic granites occur only in the basement complex in Jos plateau. Since corundum crystals in alkali basalt are xenocrysts, trace elements may indicate differences of original hosts of xenocrysts. Nigerian sapphires can be ideal samples to discuss chemical variation of xenocryst host for the purpose of origin determination of basalt-related sapphires.

Sapphires displaying a golden sheen are known as “gold sheen” sapphires in the trade. Gold sheen sapphires are believed to be mined at northeastern Kenya (Bui et al., 2015). Here we report the chemical characteristics and compare with various sapphire sources including other gold sheen sapphire data previously documented. Inclusions observed in our samples are similar to those in other gold sheen sapphires documented in previous studies. Twenty-three samples were tested with LA-ICP-MS at GIA’s Tokyo laboratory, and they showed high Fe, low V contents and high Ga/Mg ratio. Samples in this study are similar to other gold sheen sapphires in Fe, Ga and V contents. The similarities indicate that these gold sheen sapphires possibly come from the same origin. Considering Kenya as a possible origin, two different types of sapphire deposits, basalt-related (Lake Turkana) or syenite-related types (Garba Tula), are known. Sapphires from both deposits are similar in Fe and Ga contents to each other, but different in V contents. Gold sheen sapphires are close to those from Garba Tula deposits in chemical features. More gemological and chemical studies are required for constructing the database for origin determination.

Trapiche patterns were formed through the successive uptake of foreign minerals which nucleated at the ridges and the unidirectional growth by the instability of boundary interfaces

The garnet shows the various types of colour-change. They are all due to the absorption band around 570nm by V³⁺, Cr³⁺ or Fe²⁺. And high V containing type shows greenish blue colour under the D65 light source. Though such colour is limited under D65, it was believed not to exist before.

The color of unheated aquamarines characterized by the Fe content is blue with green tinge. The colour changes from green to blue resulted from the reduction of Fe³⁺ to Fe²⁺ during heat treatment. The reduction occurred in samples heated berween 400 and 480 ℃ was confirmed in UV-Vis-NIR spectra. Beryl is optically uniaxial, and I collected Photoluminescence spectra from samples with the excitation laser beam’s polarization axis parallel to the crystal’s c-axis(E||C). The intensity of PL spectra collected from the heated samples grew to the broad band.

Some antique and vintage glasses produced in 19c and middle 20c have characteristic interior and used for jewelry and accessory. In this study, I perform chemical analysis of major and trace elements, to examine color origin and characteristic interior, using EDXRF, UV-VIS-IR Spectrometer, and other equipment. All measured glasses rich in Si, Pb, K respectively, and belong to “Crystal glass”.

As part of experimental education for industrial utilization of the beauty of biological resources, authors attempted to discover pearls in dissection of first grade college students, at experimental education of biological sketches. It will be explained the reactions of students and how to use jewells to education in the future.

In recent years, nucleated acoya cultured pearls produced from Akoyagi have diversified beads size. Originally Akoya cultured pearls began in Mie Prefecture's ago-Bay during the Meiji era. It took advantage of the habit of trapping foreign bodies inside the body with the same components as shells. Initially it began with culturing true circle pearls of 3 to 5 mm. At the Japan Pearl Promotion Organization, the size of bead nucleated Akoya cultured pearls cultured in Japan is published as 2 to 11 mm. In recent years, Seawater and freshwater-produced cultured pearls circulating in the market are getting lost by size. Therefore, we considered the minimum and maximum size of the nucleated Akoya cultured pearls that are currently circulating and also about those production area.

“Teri” which is one of the quality elements of pearls is composed of brightness and interference color. Some study reported that these components were correlated. We analyzed the relationship between interference color and brightness because there were exceptional pearls which have good brightness but weak interference color expression. We considered that the expression of interference color is related to the thickness of the crystal layer.

The shell used for cultured pearl consist of nacreous structure , prismatic structure and their intermingled layers. It’s said that the limited golden pearl is faded, it’s regarded a prismatic layer and intermingled layer as a factor.

Sango pearl is the trade name for pink cultured Japanese Akoya pearls developed using pink coral beads by one Japanese pearl farming company in Uwajima, Ehime prefecture (Matsumoto Pearl). The pink coral used is considered as the precious coral Corallium elatius that is harvested along the Pacific coast of Japan, especially the coast of the Kochi prefecture (1). Sizes of ten partially drilled Sango pearls examined were 5.60–6.00 mm in diameters. No color concentrations were observed down the drill holes or anywhere on their nacreous surfaces using a microscope. The nacre thickness measured between 0.12–0.40 mm under the microscope using a small table gauge. The different nacre thicknesses were also visible in real-time X-ray images. Expectedly the pearl colors seemed to be related to nacre thicknesses: Thin nacre produced a stronger pink hue, while thicker nacre resulted in a lighter pink. The UV-Vis reflectance spectra were also related to the nacre thickness. The UV-Vis spectra of the pearls possessing thin nacre also matched the coral beads more closely, albeit with a lower reflectance, while pearls with thicker nacre revealed higher reflectance, as would be expected for lighter-colored pearls. By correlating the coral pigments with the maximum visible reflectance spectrum at 482 nm, the point of least reflectance, the relationship between nacre thickness and the visible spectra of the pearls could be gauged. The intensity at 482 nm indicates that the pink color of Sango pearls most likely originates from their coral nuclei.