{"id":4512,"date":"2026-10-07T11:15:43","date_gmt":"2026-10-07T11:15:43","guid":{"rendered":"https:\/\/gems2u4ever.com\/?p=4512"},"modified":"2026-10-07T11:15:43","modified_gmt":"2026-10-07T11:15:43","slug":"fenetre-saphir-taille","status":"publish","type":"post","link":"https:\/\/gems2u4ever.com\/en\/fenetre-saphir-taille\/","title":{"rendered":"Qu\u2019est-ce qu\u2019une fen\u00eatre dans un saphir ?"},"content":{"rendered":"
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In a faceted sapphire, light should enter through the crown, reflect inside the stone and return towards the eye. When the proportions do not support that return, a pale or see-through area may appear in the centre. This is called a window.<\/p>\n

For the complete buying framework, read our guide to choosing a natural sapphire<\/a>.<\/p>\n

A window can make it seem as though you are looking through the stone. A contrasting object beneath the sapphire may be visible through part of its centre. This observation is useful, but it is not a test of whether a stone is natural.<\/p>\n

Why does a window form?<\/h2>\n

A common cause is a shallow cut, particularly pavilion angles that allow light to escape through the bottom instead of returning towards the viewer.<\/p>\n

Overall depth alone is not a complete diagnosis: the individual facet angles, orientation of the stone and viewing direction also matter.<\/p>\n

Face-up window or tilt window?<\/h3>\n

Assess the sapphire from directly above first. A see-through area that appears only when the stone is tilted may be a tilt window, which can occur even in a well-cut gemstone. It should not be confused with a large window that remains obvious in the normal face-up view.<\/p>\n

Is every window a serious flaw?<\/h2>\n

Its significance depends on its size and visual impact.<\/p>\n

A small area of transparency may be an acceptable compromise in a stone with an unusual colour, a sought-after origin or a difficult rough shape. A large central window, however, can greatly reduce apparent brilliance and colour saturation.<\/p>\n

A strongly coloured sapphire may look paler at the window because light is escaping through it.<\/p>\n

Why are some sapphires cut shallow?<\/h2>\n

A cutter may have to balance several objectives:<\/p>\n