Adolf Peretti

GRS Gemresearch Swisslab/Peretti Museum Foundation · Senior Lab Gemologist and Curator

We here report on a well-preserved juvenile lizard specimen in Albian amber (ca. 110 mya) from the Hkamti site in Myanmar. This new taxon, Retinosaurus hkamtiensis gen. et sp. nov., is represented by an articulated skull and the anterior portion of the trunk, including the pectoral girdle and forelimbs. The ocular skeleton (scleral ossicles) and ey...

Scincidae is one of the most species-rich and cosmopolitan clades of squamate reptiles. Abundant disarticulated fossil material has also been attributed to this group, however, no complete pre-Cenozoic crown-scincid specimens have been found. A specimen in Burmite (99 MYA) is the first fossil that can be unambiguously referred to this clade. Our an...

When a vertebrate carcass begins its decay in terrestrial environments, a succession of different necrophagous arthropod species, mainly insects, are attracted. Trophic aspects of the Mesozoic environments are of great comparative interest, to understand similarities and differences with extant counterparts. Here, we comprehensively study several e...

We here report on a well-preserved juvenile lizard specimen in Albian amber (ca. 110 mya) from the Hkamti site (Myanmar). This new taxon is represented by an articulated skull and the anterior portion of the trunk, including the pectoral girdle and forelimbs. The scleral ossicles and eyelid are also visible, and the specimen exhibits pristine detai...

Recent publications have been actively recommending strong embargos on Burmese amber trade and research. Although the motivation of these actions seeks to prevent armed groups from obtaining capital via amber trade, which in the views of the authors helps further fueling the armed conflict, here, I demonstrate that this claim is not accurate. In th...

Oculudentavis khaungraae was described based on a tiny skull trapped in amber. The slender tapering rostrum with retracted narial openings, large eyes, and short vaulted braincase led to its identification as the smallest avian dinosaur on record, comparable to the smallest living hummingbirds. Despite its bird-like appearance, Oculudentavis showed...

The Attenuated Total Reflection (ATR) technique coupled with a microscope allows analysis of specimens without any preparation, spatially correlated with the specimen’s morphology. These characteristics make micro-ATR systems very useful for studying gemstones and in particular amber samples. Indeed, in this report the micro-ATR technique was use...

We describe a unique three-dimensionally preserved fossil down feather from the Late Cretaceous of Myanmar. The morphology is highly congruent with Stage IIIb of the widely accepted Prum and Brush model of feather evolution-development. This makes the new specimen the first evidence of this developmental stage in the fossil record. The Stage IIIb d...

Oculudentavis khaungraae was described based on a tiny skull trapped in amber. The slender tapering rostrum with retracted osseous nares, large eyes, and short vaulted braincase led to its identification as the smallest avian dinosaur on record, comparable to the smallest living hummingbirds. Despite its bird-like appearance, Oculudentavis showed s...

Fluid inclusion analysis including Raman spectroscopy within in the famous vibrant red spinels from Mansin (East-Mogok) have revealed that the spinels are formed from sulfur-dominated chloride carbonate melt in an extremely reduced acid environment. It is the first comprehensive model for the formation of Burmese spinels that may also help to under...

The new world record for the largest laboratory-grown diamond crystal is 60.00 ct and this gem was produced during the first week of July 2015 at the New Diamond Technology (NDT) facility in St. Petersburg (Russia) during a visit by Branko Deljanin, CGL-GRS (Canada). In April 2015 NDT produced experimentally 32.26ct colorless gem quality diamond cr...

A new type of synthetic blue diamonds appeared on the market. These diamonds were identied as CVD-grown. Optical spectroscopy revealed that they are of type IIa and their colour is caused by strong absorption of very intense silicon-related SiV-center (negatively charged Silicon and Vacancy centre). A structural and chemical layering was identied b...

Whereas colored andesine/labradorite had been thought unique to the North American continent, red andesine supposedly coming from the Democratic Republic of the Congo (DR Congo), Mongolia, and Tibet has been on the market for the last 10 years. After red Mongolian andesine was proven to be Cu-diffused by heat treatment from colorless andesine start...

Chemical profile analyses by LA-ICP-MS and EMPA analysis revealed characteristic chemical differences between different colour zones in copper-bearing tourmalines from Mozambique and Brazil. From the core to the rim of the tourmaline crystals chemical variations were found for the elements Be, F, Mg, Ti, Fe, Cu, Zn, Mn, Sb, Nb, Ta, U, Th, Pb...

Apatites derived from different rock types have distinctive absolute and relative abundances of trace elements including rare-earth elements (REE). [1] In this study, apatite inclusions in natural gem-quality corundum and spinel were analysed. They originate from the world’s most important mining areas including Myanmar, Vietnam, Sri Lanka, Ma...

The crystal structure of johachidolite, CaAl[B3O7], (Cmma, a = 9.767(2) b = 11.723(3), c = 4.3718(5) angstrom, V = 408.3(1) angstrom(3), Z = 4) has been refined (R1 = 2.5 %) from a light-green gem-quality crystal from the Mogok gem-mining district in Myanmar. A fragment from the same gem was measured by electron microprobe and Laser-Ablation Induct...

Pezzottaite is a new mineral from the Sakavalana pegmatite, located 25 km south of the village of Mandosonoro, southwest of the town of Antsirabe, 140 km southwest of Ambatofinandrahana, in Fianarantsoa province, central Madagascar. It usually occurs as isolated crystals that can have three distinct habits: (1) irregularly shaped flat masses that f...

The crystal structure of the rare hexagonal mineral painite [a = 8.724(1), c = 8.464(2) Å] from Mogok (Myanmar), with the ideal composition CaZrB[Al9O18], was re-determined by single-crystal X-ray diffraction. Structure refinements were performed in space groups P63/m and P63. The centrosymmetric P63/m model yielded excellent agreement (R1 = 1.44%,...

In 2002, a new gem mineral of commercial importance was discovered. In accordance with the need for all new mineral discoveries to be scientifically characterized (see Nickel and Grice, 1998), the gemological community anxiously awaited the results of tests to positively identify the new mineral (Hawthorne et al., 2003, Hawthorne et al., submitted...

Pezzottaite, ideally Cs(Be2Li)Al2Si6O18, is a new gem mineral that is the Cs,Li-rich member of the beryl group. It was discovered in November 2002 in a granitic pegmatite near Ambatovita in central Madagascar. Only a few dozen kilograms of gem rough were mined, and the deposit appears nearly exhausted. The limited number of transparent faceted ston...

Most Russian hydrothermal synthetic rubies and pink, orange, green, blue, and violet sap-phires - colored by chromium and/or nickel - reveal diagnostic zigzag or mosaic-like growth structures associated with color zoning. When the samples are properly oriented, these internal patterns are easily recognized using a standard gemological microscope in...

Gemologist Dr A. Peretti reports on the sensational sales of two rare and historical jewelry pieces recently auctioned in Sotheby's New York and Phillips Geneva

Dr. A. Peretti, founder and director of GRL Gemresearch Laboratory, Lucerne, Switzerland, speaks on the origins of sapphire and ruby and introduces the color terms pigeon's blood, cornflower blue and royal blue.

Seleccionar todos Título: Rubíes de Mong Hsu Autores: Peretti, Adolf; Schmetzer, Karl; Bernhardt, Heinz-Jürgen; Mouawad, Fred Revista: Boletín del Instituto Gemológico Español, 1996 JUL; (37) Página(s): 42-62 ISSN: 02107228. © UCM 2012, Biblioteca de la Universidad Complutense. Inicio | Revistas | Artículos | Boletines | Mis Suscripciones | Compati...

Synthetic alexandrite is being flux-grown in Rz~ssia in a molybdenum-, bismuth-, and germanium-bearing solvent by means o{ the reverse-temperature gradient method. Characteristic properties include habit, twinning, growth patterns, residzial flux inclusions , trace-element contents, chemical zoning, color zoning, and spectroscopic feat~zres in the...