Opal, as a gem, is called opal in English, transliterated as opal in Chinese, and also translated as OPAL by some people. It is a precious opal and a hydrate of silicon dioxide. The value of opal depends on many factors, such as hue, brightness, pattern style, color layer thickness, defect status and color change game, etc. These factors all play an important role in the evaluation of opal value. Opals are usually priced in carats. Other important factors include cutting, grinding, size and shape.
Opal is not produced in China. You can only find it online. Generally, the price of natural black opal ranges from thousands to tens of thousands, and the assembled opal is about 100 yuan. Man-made Forget it.