Gemmological Characterisation of Sapphires from Yogo Gulch, Montana
A look at the mining and distinguishing characteristics of this naturally vibrant blue sapphire.
Accurate Reporting of Key Trace Elements in Ruby and Sapphire Using Matrix-Matched Standards
Presents a group of corundum standards developed by GIA to improve the accuracy and efficiency of its laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) instruments.
Near-Colourless HPHT Synthetic Diamonds from AOTC Group
Presents the gemmological and spectroscopic properties of a suite of synthetic diamonds grown by AOTC using high pressure and high temperature.
“Jedi” Spinels in Mogok
Documents a series of visits to Myanmar in search of exceptionally bright pinkish red spinels possessing no dark tones.
Beryllium Diffusion of Ruby and Sapphire
The heat treatment of corundum involving lattice diffusion of beryllium (Be) at temperatures over 1800°C has become a major issue in the gem trade.
Rubies and Sapphires from Winza, Central Tanzania
Since late 2007, rubies and sapphires have been mined by hand methods from both eluvial and primary deposits at Winza in central Tanzania.
Gem Localities of the 2000s
The past decade saw some impressive discoveries of diamonds and coloured stones.
A study of the gems in ciborium from Einsiedeln Abbey
The gemstones that adorn a late-16th-century ciborium from Einsiedeln Abbey in Einsiedeln, Switzerland.
A Look Inside a Remarkably Large Beaded South Sea Cultured Pearl
A study of the nacre and the cavity of a large Pinctada maxima cultured pearl yields a theory on the specimen’s formation.
Sapphires from Thammannawa, Kataragama Area, Sri Lanka
The February 2012 discovery of high-quality blue sapphires at Thammannawa near Kataragama in south-eastern Sri Lanka has intensified gem mining and exploration in the surrounding area and all over the country.