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| 背面描述 | The reverse features a full-color satellite photograph of the Richat Structure, known as the Eye of the Sahara, rendered across the central field in vivid hues of blue, orange, purple, and gold, accurately conveying the circular erosional formation as seen from orbit. The image is applied using precision color-printing technology over an antiqued silver surface, with the surrounding field left in relief to frame the colored insert. The inscription Kalb ar-Riszat, the Arabic-derived name for the formation, is incused in bold lettering along the lower arc of the coin within the uncolored silver border. The contrast between the vibrant colored center and the antiqued silver surround creates a dramatic visual effect characteristic of the Space Day series issued by the Mint of Poland. |
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| 边缘 | Reeded |
| 铸币厂 | 登录 以查看详情 |
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| 附加信息 |
The Eye of the Sahara — formally the Richat Structure — is a 40-kilometer-wide geological dome in Mauritania that spent decades puzzling researchers who initially assumed it was an impact crater. It isn't; erosion of a symmetrical anticline is the accepted explanation, though the debate ran well into the 1990s. Its fame in numismatic and collectibles markets stems almost entirely from its visibility from low Earth orbit, where it functions as a navigational landmark for astronauts. Niue's Space Day series exploited that association directly.