Nuummite – the Origin of Colour
This article by Guy Lalous ACAM EG summarises a technical article from The Journal of Gemmology discussing the origin of colour and conditions of formation in violet-to-blue Nuummite from Simiuttat, Greenland. Nuummite is an iridescent orthoamphbiole rock found in the Nuuk Distruct in south-west Greenland. It has only been known in the trade since 1983. […]
Gem Central Exploring Ruby Treatments with Julia Griffith FGA DGA EG
Gem-A gemmology and diamond tutor Julia Griffith FGA DGA EG led a gem central titled Exploring the Differences between Glass In-filled, Flux Healed and Lead Glass-filled Ruby, in an informative and engaging gem central evening. Julia summarises the evening here for those that missed out. The latest Gem Central evening held on 30 April at […]
The Most Underappreciated Gemstone? Why We Love Rock Crystal
Everyone knows that lucky April-born souls have been blessed with one of the most prestigious birthstones: diamond. However, there is an alternative birthstone for the month and it’s a ‘hidden gem’… so to speak! Gem-A Member, Julia Griffith FGA DGA EG explains why rock crystal is worth your time and attention. Rock crystal is the […]
Zircon from Vietnam: Properties and Heat Treatments
This article by Guy Lalous ACAM EG summarises a study on the gemmological and physical properties of brown zircon from the Central Highlands of Vietnam, together with its chemical composition, Raman, Fourier Transform Infrared Spectroscopy (FTIR) and Ultraviolet Visible Near InfraRed (UV-Vis-NIR) spectroscopic features. Zircon, zirconium silicate (ZrSiO4) crystallises in the tetragonal system and has […]
The Myths, Legends and Controversy Behind Ancient Preseli Bluestone
Sarah Steele FGA DGA discusses the unusual history of ancient Preseli bluestone. If ever there was an unlikely candidate for a gem material then Preseli spotted dolerite, would at least at face value, be it. Over the last five or six years however it has appeared on the market in increasing quantities, both as jewellery and […]
A Passion For Working Fire Obsidian
Tom Dodge, a retired geologist living in Arizona, USA has been an avid rock collector for 57 years, a registered professional consulting exploration geologist for 35 years, a skilled flint knapper for 16 years and a budding lapidary for two years. Here, he takes a look at fire obsidian, an enchanting and little-known material. Collecting and working fire obsidian […]
Birthstone Guide: Aquamarine for Those Born in March
Those born in March are lucky enough to have two birthstones: the beautiful blue of aquamarine and the mysterious red-spotted bloodstone. Here, we delve into the history and mystical properties of aquamarine and why this sky blue gem is said to be a talisman of good luck, fearlessness and protection. The blue hues common to this […]
Ruby and Pink Sapphire from Aappaluttoq, Greenland
This article by Guy Lalous ACAM EG summarises a study of the geology, gemmological and physical properties of rubies and pink sapphires from Aappaluttoq, one of the last pristine spots on the planet not far from the arctic circle. What is the difference between metamorphism and metasomatism? When rocks change because of an increase in […]
Field Trip: Exploring the Wonders of Myanmar
Gem-A member Patricia Campion reports on a recent gemmological field trip to Myanmar, highlighting her experiences of gemstone market places, the Myanmar Gems Museum, in Yangon, and seeing mushroom tourmaline for the first time. On Christmas Day, our group met in Yangon for a gemmological tour of Myanmar organised by Pauline Jamieson for the Scottish Gemmological […]
The Tale of the Mouawad-Tereschenko Blue Diamond
Jack Ogden FGA looks into the story of the world’s second largest blue diamond, the Mouawad Blue Diamond, previously known as the Tereschenko Blue Diamond. In the summer of 1984 David Warren, now Senior International Jewellery Director at Christie’s, received a phone call from the auction house’s bank manager with a question: “Do Christie’s sell […]
