Jade Identification --Scientific Method

There were works on jade identification theory and practice  since the Song and Yuan dynasties. While there are so many divergent views on jade identification, the scientific identification of the ancient jades has been recognized by industry, government and academia. I have done a study presented to a Taipei conference only served as a practical summary to them. In addition, my study attempts to provide a reference comparison method to identify handed down jades without unearthed reports. In the article on Mineralogical Studies of Archaic Jades (p. 199 no. 32, Acta Geological Taiwanica), Prof. Tsien, H. H. has presented the scientific method on jades identification. Since then, the scientific method on jades identification by Prof. Tsien has gained universal acceptance from both academia and professionals. According to Prof. Tsien, Identification of jade antiques consists of three aspects:  
1. authenticity of jade antiques , 2. material composition identification, 3. time period verification.
Authenticity of jade antiques may be verified through certain physical and chemical characteristics including dissolved pits, cleaving veins ,differential weathering, diffusive markings( which should not be mistaken as raw jade skin ), exposure crystals and mineral attachments such as gold placer, Deterioration marking(Aging Spot or ant's leg or cow's hair), underground deterioration and secondary crystal planes which are suitable to serve criteria of authenticity of jade artifacts:
  Cleaving Veins:The cleaving veins seen inside the jade artifact are caused by the interaction of jade to the physical factors of heat and pressure. They are different from the cracks caused by percussion. Usually there are no exterior cracks for cleaving veins and exterior cracks are common phenomena for cracks caused by percussion. These are crystals from the jade itself due to physical factors such as heat and pressure. Underground Deterioration: The channel like natural deterioration are caused by underground chemicals. Additionally, material composition may be reliably and scientifically identified through instruments such as a reflectometer and Raman spectrometer. Generally, nephrite has a refractive index of 1.61 (jadeite has a refractive index of 1.66 )or has a prominent mode within the low wavenumber range of 600-800 and around 3700 high wave number reading via Raman spectrometer. In addition, the hardness of nephrite is 6.5 to 7, while the serpentine has a hardness of 5 to 6. The hardness can be tested by a knife on an not important spot.
To identify the time period of a particular jade artifact may be based on factors including carving style, motifs and designs of the object  considered and characters( if any ) on the jade, (please read information on  Chinese jade chronology.). Above all, according to jade identification expert Dr. Daphne Rosenzweig, jade artifacts should be dated via analytic and systematic approaches. An excellent paper by Eric J. Hoffman is highly recommended to read for more information.