求翻译：石，是中国印章重要的物质载体，但是在元代之前。人们多是采用金，银，铜，铁，玉，象牙作为印章的材料。因为这些材质的坚硬，只能由专业工匠刻制。这在很大程度上制约了印章艺术的发展。是什么意思？

Stone, is the important material carrier of the Chinese seal, but before the Yuan Dynasty. Most people is the use of gold, silver, copper, iron, jade, ivory seal materials. Hard because these materials can only be engraved by a professional craftsman. This has restricted the development of seal art.

Seal Rock, is China's important material carriers, but before the next generation. Most people are using gold, silver, copper, iron, and Jade, and ivory as a seal of the material. Because these materials can only be the hard, engraved by a professional artisan. This seal is greatly constrained by th

The stone, is the Chinese seal important material carrier, but before Yuan Dynasty.The people many are use the gold, the silver, the copper, the iron, the jade, the ivory take the seal the material.Because of these material quality hardness, only can make by cutting by the specialized artisan.This h

Stone, is an important physical carrier of Chinese seal, but before the Yuan dynasty. People are using gold, silver, copper, iron, jade, ivory, as seal material. Because the material is hard, only by professional craftsman engraving. This is to a large extent restricted the development of seal art.

stone, which is important in Chinese seal material carriers, but before the next generation. Most people are using gold, silver, copper, iron, and Jade, and ivory as a seal of the material. Because these materials can only be the hard, engraved by a professional artisan. This seal is greatly constra