gemmology

GEMMOLOGY WORKSHOPS

For several years now, the Maison Tournaire has been offering introductory workshops in gemology (the study of precious stones). Thanks to his passion for gemstones and his background as a teacher, Mathieu Tournaire brings these workshops to life, enabling visitors to discover the Maison Tournaire and its jewels from another angle.

Succumb to the beauty of stones

Our gemology workshop allows participants to discover the science of stones, their meaning and how a jeweler handles and observes them. It also gives you another way of discovering the Maison Tournaire and its unique creations, which you will have the chance to handle during this gemology workshop.

The workshop is divided into 3 main parts

The first part is more theoretical, providing the basic knowledge and vocabulary needed to understand the workshop.

-The second part is devoted to the discovery of precious stones. La Maison Tournaire does not shy away from breaking down preconceived ideas about gems. Diamonds, sapphires, opals and Tanzanites are all in your hands, and you can observe them at your leisure through a x10 magnifying glass.

-The final part of the workshop allows participants to have direct contact with the Tournaire creations, as it is dedicated to their presentation. From iconic jewels such as the trilogy Alchimie ring or the French Kiss ring to more intriguing pieces such as the Archipolis collection, you will discover, accompanied by a gemologist from the Maison Tournaire, the spirit of the Maison and its values.

Thanks to its convivial and participative dimension, this workshop will enable you to immerse yourself in the world of Jewellery and gemology.

You can contact your nearest Tournaire boutique for more information.

PRECIOUS STONES

Tournaire uses the most precious stones to create exceptional jewelry with timeless charm. Philippe and Mathieu Tournaire create jewelry with finesse and elegance thanks to the unique know-how of Jewellery.

The color palette of gemstones

As far back as we can remember, man has always made jewelry. To mark his passage, to evoke something or to symbolize his success. Generally speaking, he's been fascinated by what he finds in nature, especially beautiful stones. But these are just stones, chosen for their particular color or brilliance, which are then enhanced by cutting and polishing. The value we attribute to a stone is not necessarily related to its price; it all depends on what value we attribute to it, sentimental or commercial... Even a common stone can have value, depending on what it evokes in us. For example, if two lovers are walking on the beach and find a pebble together, it will have much more sentimental value than another stone. Price is often synonymous with rarity for a stone, for example, shells had a high market value for people who lived inland, as they were rare for those who didn't travel.
When I choose a stone, it's not only with the eyes but with the heart too, I choose it simply because it's beautiful. Its color must "sparkle", the stone must be alive. I don't choose a stone for its name, but for the optical effect it creates.

But before I introduce you to the stones that make up what I call my color palette, I need to give you the keys to understanding how I look at stones. The stones used in Jewellery are "gems", hence the name of the science that studies them: gemology. All elements beautiful enough to be set in jewelry are considered gems. It's important to distinguish between the different types of stones that exist. There are, of course, natural stones, found by man in nature with their own unique characteristics. Thanks to the evolution of techniques and research, there are also synthetic stones. These are man-made but have the same physical, chemical and optical properties as their natural counterparts, such as synthetic sapphire.
Finally, there are also imitation stones, i.e. counterfeits of natural stones that can be both natural and synthetic. They imitate the appearance, color and optical effect of natural stones, but lack their chemical or physical properties. Synthetic zirconium oxide, for example, is the best-known imitation of diamond, but transparent glass can also be considered an imitation.

When choosing a stone, I take into account its physical properties, particularly its hardness, i.e. its resistance to scratching and abrasion. To measure this value, we use the Mohs scale, with increments ranging from 1 for the softest, to 10 for the hardest. To give you an idea, we consider that gems with a hardness of less than 7 can lose their brilliance and polish over time, due to the presence of quartz in the ambient dust, but also because of the things we put jewels through when we wear them. They must therefore be worn, cared for and stored with care.
Another important indication when choosing a stone is its weight. We mainly use the carat as the unit of mass of a gem, equivalent to 0.2 grams. This value has been used in the gem trade since antiquity. The word comes from the Greek "keration", the name of the carob tree seed renowned for its constant weight of around 0.2 grams. But there's a distinction to be made: carat is also used for precious metals such as gold, in which case it designates purity. Thus, 24carat gold is 100% pure, but soft, which is why 18 carat gold is more often used in Jewellery, like all the major brands. This gold is made up of 75% gold, with the remaining 25% giving the alloy its hardness and color.

This percentage may include silver, copper, palladium... in varying proportions.
Until 2002, the term "precious stone" was used to refer to diamond, ruby, sapphire and emerald. This was a historically arbitrary classification, which implied that there were precious stones and less precious stones... Since February 1, 2002, all the qualifying terms of the old classification have been repealed, and the term "gemstones" is now used to characterize all stones formed in natural deposits. I simply like to use the terms "stones" or "pebbles" to refer to these treasures.

Jewellery is designed according to the choice of stone: I can't afford to mount a gem that's too fragile if it's exposed to shocks, otherwise I adapt the jewel so that it's protected. Finally, the carat is important, as it will directly influence the price of my raw material. But I don't choose a stone based absolutely on its size, as I always say: "Better a small pretty one than a big ugly one".

Mohs' scale

Scale	Reference mineral	Means for determining scratch hardness
1	Talc	Friable under the nail
2	Gyspe	Scratches with the nail
3	Calcite	Beamable with one piece (copper)
4	Fluorite-Perle	Easily scratched with a knife
5	Apatite	Scratchable with a knife
6	Orthose-Opale-Tanzanite	Scrapable with file
7	Quartz-Grenat-Tourmaline	Scratch with a file
8	Topaz-Emerald	Tungsten carbide strippable
9	Corundum	Strippable with silicon carbide
10	Diamond	Strippable with another diamond