Reversible Colour Modification of Blue Zircon by Long-Wave Ultraviolet Radiation
Determines whether blue zircon, inadvertently altered to brown by exposure to long-wave UV radiation, can be restored to its original colour through the use of incandescent light.
Vanadium and Chromium-Bearing Pink Pyrope Garnet: Characterisation and Quantitative Colorimetric Analysis
This type of pink pyrope garnet, believed to have been mined in Tanzania, shows a distinct colour-change phenomenon resulting from its unique chemical composition.
The Very Deep Origin of the World’s Biggest Diamonds
Explores an exceptional family of diamonds, referred to as “CLIPPIR” (Cullinan-like, Large, Inclusion-Poor, Pure, Irregular and Resorbed), that formed in a super-deep environment.
True Colours of “Dalmatian Jasper”
Discusses the mineralogical composition and provenance of this spotted decorative gemstone.
Saltwater Pearls from the Pre- to Early Columbian Era: A Gemmological and Radiocarbon Dating Study
Examines 85 saltwater natural pearls, reportedly harvested from the Caribbean islands off the coast of Venezuela during the early 16th century, to determine their age.
Characterisation of Mg and Fe Contents in Nephrite Using Raman Spectroscopy
Evaluates the usefulness of Raman spectroscopy in distinguishing the colour varieties of nephrite based on the relative ratio of Mg to Fe concentration.
Japanese Jadeite: History, Characteristics and Comparison with Other Sources
Examines the sources, colour, texture and chemical composition of jadeite from Japanese deposits.
Causes of Iridescence in Natural Quartz
Describes the occurrence of iridescence, and the role of differential etching, in quartz crystals from India’s Jalgaon District.
A New Find of Danburite in the Luc Yen Mining Area, Vietnam
Reports on a recently discovered eluvial deposit of honey yellow danburite with excellent transparency.
Colour Phenomena of Blue Amber
Investigates the presence of fluorescence, rather than iridescence, as the cause of colour in blue amber from the Dominican Republic and Indonesia.