Gemmological Characteristics and Exploitation Prospects of Silicified Wood from Burma

Silicified wood is wooden fossil from ancient tree formed by geological process and mainly consists of SiO₂.The silicified wood samples from Burma are studied by using polarized microscope and infrared spectroscope.The results show that there are two types,one is chalcedony-type silicified wood,which consists of cryptocrystalline quartz and a little granular quartz,with refractive index of 1.54,density of 2.52 g/cm³,hardness of 6.6,and dark-brown and white floccule inclusions.A group of IR absorption peaks are at 1 088,556.1,462.8 cm^-1.The other is opalline-type silicified wood which consists of opal and a little cryptocrystalline quartz,with refractive index of 1.45~1.46,density of 1.92~2.07 g/cm³,hardness from 4.95 to 5.17.It is of woody fibrous structure orderly in the vertical-section and small pore space in the across-section.Some of the opaline-type silicified wood have changed to chalcedony-type silicified wood.A group of IR absorption peaks are at 1 102,787,474 cm^-1.It is considered primarily that the silicified wood from Burma has the favorable exploitation prospects.