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Celebrating the 160th anniversary of Minerva, the Montblanc 1858 Geosphere honours the heroes of mountain climbing with a professional-grade, innovative timepiece. Built for those who travel the world in their perpetual quest for exploration, it expresses respect for true mountaineers as it is dedicated to the Seven Summits Challenge – the holy grail of climbers. The combination of materials such as steel and ceramic underlines the high quality and exclusiveness of this timepiece. On the dial, the world’s seven summits are marked with red dots on two turning globes and are also engraved on the case back. The timepiece features a new manufacture world-time complication developed by the Montblanc watchmakers in Villeret: two domed globes, turning in opposite directions, that complete a full rotation in 24 hours. Both are surrounded by a scale with the 24 time zones, along with a day and night indication in contrasting colours. This provides an instinctive way of appreciating the different time zones, aided by SuperLumiNova® applied to the continents for increased visibility and performance at night. Specifications Brand: MontblancCollection: Montblanc 1858 Model: Montblanc 1858 AutomaticCase material: Stainless SteelDial colour: Black Strap colour: BrownCase diameter: 42.00 mmStrap: LeatherMovement: AutomaticTime display: Analog
Product reference: 4520440

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The 4C's
The 4C's of a diamond are the four key characteristics that determine the quality and value of a diamond: cut, carat weight, color, and clarity. Together, these four characteristics are used to evaluate the quality and value of a diamond, and are considered when determining a diamond's price.
Carat
The weight of a diamond is expressed in carats and points (1 ct = 100pt). ‘Carats’ come from ‘Carob’ seeds, which were originally used for their constant weight in nature (1 ct = 0.2 g). The carat and the color are the factors that influence the most the final price of the diamond.
Clarity
The clarity is a gemstone's relative freedom from internal imperfections. These imperfections are observed with a x10 magnifier ('loupe') and affect the final value of the diamond differently.
Color
Diamonds are found in nature in different colors. White diamonds can be more or less yellow and are categorised with a letter between D (commonly known as ‘River’) to Z . The different naming systems vary depending on the certifier. Diamonds are also found in all colors; the rarest colors are classified as Fancy-colored diamonds.
Cut
The cut is the diamond’s shape. A cut grade describes the proportions of the cut and the quality of its symmetry and polish. A perfect cut makes the best sparkle.