Posts by Isaiah Triollet
Corundum: an exceptional family of gems
Few minerals can claim to have given rise to two of the world's most famous precious stones. Yet ruby and sapphire are simply two faces of the same mineral species: corundum.
The beryl family: crystalline elegance
When we think of great precious stones, emerald naturally comes to mind. Yet few people know that this gem, together with morganite, heliodor, goshenite, aquamarine and the very rare red beryl, belongs to a single mineral species: beryl.
Daniel Brush: when light becomes matter at L’École des Arts Joailliers
Daniel Brush: when light becomes matter at L’École des Arts Joailliers
Garnet: diversity, history and mineral brilliance
A gemstone cherished by mineralogists and jewellers alike, garnet is one of the most varied and fascinating minerals in the mineral kingdom. Behind a single name lies a whole family of gems with extremely diverse compositions, colours and origins.
Blue Mellon: an exceptional blue diamond at the heart of the gemstone market
The Mellon Blue is an exceptional blue diamond weighing 9.51 carats, graded Fancy Vivid Blue by the GIA and with flawless clarity, pear-cut and currently set in a ring. Its rarity and quality make it one of the most sought-after stones. It was offered at auction on 11 November 2025 at Christie's Magnificent Jewels sale in Geneva, with an estimate of between 20 and 30 million dollars.
Zoisite: a gem of many facets
Zoisite is a fascinating mineral which, although understated in its rough form, reveals a palette of vibrant colours once cut. From blue-violet tanzanite and pink thulite to green anyolite flecked with ruby, this stone embodies mineralogical diversity.
Zircon: a sparkle of history and a record of the Earth
Zircon fascinates jewellers and collectors as much as scientists. Often overshadowed by better-known gems such as sapphire or diamond, it nevertheless deserves a place of its own.
Tourmalines: a mineral kaleidoscope
Few gems rival tourmaline’s diversity of colour. Its name comes from the Sinhalese toramali or turamali, meaning ‘stone of mixed colours’, which captures its essence perfectly. Whether rubellite red, verdelite green, indicolite blue, bright yellow, soft pink or bicoloured like the famous ‘watermelon’ tourmalines with their contrasting green and pink, tourmaline embodies the mineral rainbow.
Topaz: a gem of science, history and prestige
With its crystalline hues and sometimes fiery brilliance, topaz holds a special place in the gemstone world. Although many people picture it as a clear blue stone, it comes in a wide variety of colours and forms.
Opal: where light meets geology
With its shifting play of colour and iridescent reflections, opal occupies a unique place in the gemstone world. As an amorphous material, it falls outside traditional mineralogical classifications. From Australia to Ethiopia, each deposit has its own signature, reflecting a complex geological history and a very particular environment of formation.
