Authenticity of jade antiques may be verified through certain physical and chemical characteristics including differential weathering, diffusive markings, additive crystals and a exposed crystal plane. Additionally, material composition may be reliably and scientifically identified through instruments such as Refractometer and Raman spectrometer.
To identify the time period to which a particular jade artifact may belong, factors including carving style,motifs and designs of the object may be considered. According to well-known expert of jade identification and jade jade appraisal, Dr. Daphne Rosenzweig, jade antiques or jade artifacts should be dated via analytical and systematic approaches.
Artisans from the Hongshan Culture emphasized an object’s shape rather than surface lines or curvature. Simple and round designs are characteristic of many Hongshan Culture jade artifacts.Dual holes called holes of on the same side of the artifacts are usually seen.
A major motif of Liangzhu Culture jade artifacts is “God’s Face”, and artifacts feature slim and incised lines. Liangzhu Cultural artifacts embody two elements worthy of consideration. First, jade motifs have made an impact on jade motifs of later periods. The God’s Face motif constituted major motifs of artifacts from the Spring and Autumn Period. The curling craws shown under the God’s Face constituted the craws of dragon for the Shang and Western zhou periods. Second, many Liangzhu Culture jade artifacts have a smoothly cut surface of the motif that may be interpreted to record poignant events such as prayers or sad memories.
A major feature of Qijia Culture jade artifacts is the uni-directional hole-drilling, resulting in visibly irregular edges.Typical jade artifacts from this period are fine thin knives with very smooth surfaces.
Most jade artifacts from the Sanxingdui Culture are made of nephrite and are skillfully carved. Jade artifacts of priests and knights from this period display prominent eyes, wide ears, and decorated with special markings believed to derive from an extraterrestrial civilization.
Longshan Culture jade artifacts are multivariate, from jade kwei to jade arched pendants to jade tubes to bi-disks and notched bi-disk, all of which are elegantly and dexterously carved. The motifs and line carving styles of Longshan jades suggest these to be predecessors of Shang Dynasty jade styles.
From the available Xia Dynasty jade artifacts found, the variety of Xia Culture jade artifacts include jade ring, jade ax, notched zhang, notched bi-disk, arched plaques most of which are rather large and thin in size and have symmetrical lines. Parallel and intersection incised thin lines are used to form simple and concise motif. Moreover, many Xia jades are seen the trellis design consisting intersecting straight lines to form close and inseparable rhomboid shape that further to generate the exaggeration effect and the feeling of the mystery and solemnness that these ritual artifacts carrying.
From weighs twenty kilograms to three centimeters in length, the Shang Dynasty jade artifacts include kneeling person, pig, sheep, mythical animal, dinosaur, jar and jade plaques. It should be noted that the Shang Dynasty jade artifacts are not only made of fine quality jade but also are with extraordinary skillful workmanship. Low relief and streamlined lines done through the reduction of the surface, the square angle curling lines and the smooth dual relief lines are typical for the Shang Dynasty jade artifacts.
The carving style of the jade artifacts for the Spring-Autumn period is derived from the late Zhou dynasty and develops into more detailed pattern. The bosom motif of auspicious cloud is the typical motif for this period. The jade artifacts of the Spring-Autumn are favorable to many serious collectors. The jade carving of the Warring States is of exquisite quality. With streamlined design, most of the motifs are dragons, phoenixes, dancing ladies and crops. The low relief on the surface of the artifact applies abstract and simplified motifs while those carvings extend from the artifact apply realistic ones.
The jade carving technique of the Han dynasty is famous for its straightforwardness and is known as the eight times of carving. The main motif for western Han is the auspicious animal. The size of jade artifacts tends to become large. After eastern Han, the main motifs are the four auspicious creatures (dragon, phoenix, tiger, the couple of snake and turtle), cloud and eagle. Different from previous periods, Han Dynasty jades have modern Chinese characters reading long happiness, suitable for offspring appeared on many bi-disks jades.
The design of Tang Dynasty jade artifacts are seen to be characterized by reality and its relation to daily life. With a rich tint of Buddhism, many jade Buddhist figures are made during this period. Owing to the particular cultural development such as the Tang trio color ceramics, many jade artifacts are painted with rich colors and guilt with gold. Flying fairy of Buddhist figure is appeared as single piece jade artifacts or constitutes major motif on the artifacts. Due to the highly developed communication with foreign countries, foreigners visited China quite often that many motifs of Tang Dynasty are appeared as foreigners from the west which are called Hu people then.
The designs of Song, Yuan, Liao and Kim Dynasties jade artifacts are more daily life oriented. The main theme of many Song Dynasty jade artifacts is laden with different posture and the main themes of Liao and Kim Dynasties are the scenes of spring with birds, flowers and ponds, the scenes of autumn mountain with pine trees, deer and animals.
In the Ming Dynasty, the most important jade artifacts are those made by famous craftsman Lu Tzu-kang. The jade plaque made by him has become the standard design which calls Tzu-kang plaque. As a result, genuine Tzu-kang plaque is valuable even during the Ming Dynasty and goes without saying for later periods. The simple criteria to identify genuine Tzu-kang plaque are the material should be top grade white Hotien jade and low relief lines for the curving characters. In the Qing Dynasty, due to the emphasis of jade artifacts from the imperial court, especial from the Emperor Chienlung himself, jade artifacts of the Qing Dynasty become the last high peak in terms of quality and quantity of Chinese jade carving history.