Events and Actuality

Our futur


GemGenève 2019

From 9th to 12th may 2019

GemGenève at Palexpo

Booth : D4-4

Geneve, Switzerland


Hong Kong

From 28th to 4th march 2019
Booth : 8A06

Asia World Expo

Lantau Island – Hong Kong



Tucson Gem Show

From 5th to 10th February 2019

Booth : 331
3750 E. Irvington Rd.
Tucson, AZ 85714 – Etats-Unis


Our lastest


Gem Lab reports and commercial responsibility

The price of untreated coloured gemstones has increased exponentially in the last decades. As a result, demand is increasingly selective and requires higher levels of certification. On the other hand, treatment techniques have refined and developed. This trend has strengthened the role of gemological laboratories. A certificate from a laboratory is now an all but […]

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Kashmir sapphires’ cut

Sometimes you can guess that a sapphire comes from Kashmir just with a glance at its specific cut. This cut is typical of old European standards and was developed in the beginning of the 20th century. When mining started in Kashmir, Europe had been famous for a while for its lapidary know-how, especially thanks to […]

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Tanzania : a wall for more ethics

Tanzania is the number one producer of Tanzanite worldwide. Despite this production, Tanzania only ranks third for exportation, with 38 million dollars, behind India (Around 300 million dollars) and Kenya (approximately 100 million dollars).

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Why attending GemGenève next year

Welcome to GemGenève. This new show met the challenge of creating a new meeting place for gems and antique jewelry traders. Good choices were made on all levels and proved the high standing positioning of this first edition. “GemGeneve has established itself as the new gem show V2.0. The warm spirit, the elegance and family […]

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“Umba” Sapphires : a unique color and a unique story

Since they were discovered, Umba sapphires have captivated traders and jewelers with their amazing and unique colors (especially orange). In the mid-sixties, George Papaeliopoulos, a Greek sisal farmer living in Africa, discovered a sapphire deposit along with rhodolite, malaya garnets and emeralds near the Umba River in Tanzania. Having no background in gemology nor the gem industry, he […]

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A word with Piat’s gem cutters

Let’s walk through the door of Maison Piat’s lapidary workshop and meet with Nuon, Léa, Liselotte and Phrom, all gem cutters who kindly agreed to answer our questions.

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Blockchain’s promises

Blockchain theory appeared in the early 1990’s and in 2008, amid a global financial crisis, a decentralized version was implemented with Bitcoin. At that time confidence in banks and currencies was at an all time low.

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Cultural event : The jewels of the Crown

Last November, the Piat team went to the Louvre Museum to rediscover the jewels of the Crown of France. With Capucine Juncker, gemologist and founder of the website property of a Lady as a guide, it was a great opportunity to go through our French history again. Indeed, the destiny of these fabulous gems is […]

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The 2017 CIBJO Congress

The Congress took place in Bangkok in the presence of the Prime Minister and the Thai Minister of Trade, from 5 to 7 November 2017. One of the major objectives was to unite companies in the stone and jewelery business around the world on social and environmental issues. CIBJO hosted several sessions. One of them […]

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The World Ruby Forum

The World Ruby Forum was held in Bangkok on November 4 and our team from Piat Thailand attended it. The participants were welcomed by the Thai Minister of Trade. The objective of this forum is to promote, support, develop and share knowledge on the value and beauty of rubies, and also to develop gem trade […]

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Stability of Padparadscha Sapphire Color

Does the unstable color of Padparadscha sapphire jeopardize its designation ? Highly sought after and coveted, this exceptional stone has to deserve its name. When obtained, the Padparadscha designation can significantly raise the stones’ value. The stone must be of a harmonious pink-orange color to get the Padparadscha qualification, but that alone is not enough any more […]

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Latest auction records

A 28.04 ct Padparadscha sapphire at Christie’s sale in Magnificent Jewels & The Pink Promise on 28 November 2017. A 28.04 ct Padparadscha sapphire white gold ring (Lot No. 2064) was sold for $ 2 470 000, or about $ 88,000 per carat.

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The “Cutting” Minute

Since the dawn of time, Mankind has polished and cut gemstones to adorn its jewellery. Tutankhamun’s burial mask testifies to it, with its calibrated Lapis-Lazuli, Turquoise and Carnelian, in rectangular and trapezoid shapes. The Lapidary equipment was then very rudimentary.  

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The grandidierite

According with a hardness of 7 to 8, Grandiderite could be used in jewelry. But the gemme quality is extremely rare and locate in particular in Madagascar. Small and low purity samples were found in Sri Lanka, Namibia and Malawi. Therefore,  the Grandiderite is a stone of collectors.    

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Latest auctions : new records

The colored gemstones market is often pointed at for its total lack of transparency. While a broad documentation about diamonds can easily be found and is available on the Internet – sector-specific market studies, organized exchanges, prices index (thanks to the Rapaport list) – the colored gemstones market is blamed for being subjective and is […]

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CSR, the basics

Sustainable Development …. An old-fashioned expression. Everybody talks about “sustainable development” without even knowing what it means anymore.

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A little bit of arithmetic

The change of shape and/or faceting is an extremely common demand for stone cutter. Each stone has different characteristics (dimensions, number and position of inclusions, faceting, scratch…). Despite all of it, it is possible to establish percentages of loss depending on the change of shape. For an oval-shaped stone to transform in pear shaped stone, […]

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Oil and resin : how to understand

Emerald is a stone appreciated for its “gardens”, but these inclusions are whitish and can alter the general color of the stone. Filling cracks with oil and / or resin will reduce these inclusions. This embellishment technique thanks to oil has been known since Pliny the Elder, more than two millennia ago. Although it might […]

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Emeralds of Exception: an ever-growing value

We examined the development of Colombian emerald prices in major auctions over a 15-year period, focusing on lots with the highest bids (five lots per year).  On the graph above, a sharp yearly increase in price stands out remarkably: around 10% per year. Regarding the five highest quality lots, growth has been even more considerable, […]

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“Old mines” emeralds

Historically speaking, it hasn’t been unusual to confuse Colombian emeralds with the “old mine” emeralds associated with the Hindu Maharajahs. What are “old mine” emeralds and where exactly do they come from? In the mid-1970s, Russian geologists discovered emeralds in the Panshir Valley of Afghanistan.

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AUCTION’S FOCUS : A sapphire from Kashmir

We have seen a surge in auction prices since the early 2000’s. The records achieved by the coloured diamonds are the most publicised, but others categories of gemstones have seen tremendous growth in prices.

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Daniel Piat in 1961

This year, the Ministry of Agriculture, on which the mines depend, authorised the Chamber of Commerce laboratory to award a diploma with the aim of developing knowledge in gemology.

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New perspectives in Myanmar face to the US embargo lifting

Following the lifting of the US embargo signed by US President Barack Obama at the beginning of October 2016, which blocked the import of jade, rubies and jewellery, we have yet to see the expected growth of trade in jade and precious stones.

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The Greenery Trend

According to the Pantone Color Institute, this year’s colour will be Greenery. A very spring-like soft green, evocative of renewal and nature. Following 2016, a pastel year of Serenity and Rose Quartz, expressing harmony in a chaotic world, this year 2017, marks a real contrast.

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