Reference work entry
Grape agate is a precious type of Gobi stone. It gets this name because the agate is covered with bead-shaped spheres shaped like a bunch of grapes. Grape agate is mainly found in the area near the Chinese-Mongolian border north of Suhongtu in Alxa League, Inner Mongolia. Grape agate, wind stone and desert paint stone are known as the ‘Desert’s Three Superiors’. Grape agate forms as a result of magmatic activity and exists in large crystal cavities near a crater. In a relatively stable environment, hot silica solution condenses into small beads around a particle (e.g., sand, mud or water droplet). This process repeats, and subsequently small beads attach to the earlier bead surface to form features like a bunch of grapes. Grape agate is characterised by: (1) round and moist beads; (2) bright striking colour; (3) excellent texture; and (4) remarkable aesthetics. Red grape agate is the most popular and valuable type (Fig. 34).
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