2. Quartz stone is composed of silica, the most typical of which is crystal, which is a crystal structure. Unlike jade, jade is composed of calcium carbonate, calcium magnesium silicate, sodium aluminum silicate and a small amount of chromogenic elements. The crystal structures of jadeite and quartzite are different, and jadeite is mostly amorphous.
Direct contact is very important. The real ancient jade has a long history, heavy feel, soft and smooth appearance, natural color, neat knife work and moist patina. Xinyu doesn't have these feelings. Antique jade appeared in the Song Dynasty. At that time, someone forged chicken blood with rainbow grass. After the Qing Dynasty, there were more and more fakes, and unprecedented creations appeared, such as "dog jade", "sheep jade" and "wind jade", which attracted people to be fooled.
Extended data:
Jade quality appraisal
(1) color
Green is the best jade, and the value of red and purple jade is only 1/5 of green jade. If jade contains red, purple, green and white, it is called "Fulu Xi Shou"; If it only contains red, green and white, it is "Fu Lushou".
The dull and yellow ones are inferior. If it is monochrome jade, the color is better.
(2) Pass
Transparent and crystal clear as glass, no dirty spots, no chaff and no astringency is the top grade. Translucent and opaque jade are called intermediate jade and ordinary jade respectively. Before and during the Qing Dynasty, jade with red, green and white colors was called jadeite.
In modern times, jadeite refers to generally transparent jade. At present, jadeite is transparent and green.
(3) uniforms
The color of jade is uniform. Although it contains white and green, the color is uneven, so the value is very low.
References:
Quartz Stone-Baidu Encyclopedia Jade-Baidu Encyclopedia