Study On Gemological, Mineralogical Characteristics And Color Genesis Of Ammolite In Canada

196 pieces of ammolite triplets are selected as spcimens.The samples are classified according to color, such as red, green, blue, purple and so on. The gemological characteristics of these samples are taken record and the gemological index are tested.Color i5 is used to measure the color index of all samples, including hue, saturation,and brightness. Analysis the difference of color index between these samples, in order to find some certain regularity. The photo experiment is designed to record the color of samples in different shooting angles. So we could find the change rule and find the right laws of physics to explain the phenomenon. Through FE-SEM with EDS the structure of samples is observed and the thicknesses of the layers of aragonite are measured. When comparing the average of layer thickness between different colors,we could find out which physical laws matches for the situation. Then we could analysis the components in different regions with EDS.The result showed that the color of the most samples is red, followed by green, blue and purple the rarely. As the viewing angle transferring, the color is from red to green in turn according to physical spectrum color sequence. The absorption peaks through FTIR mainly indicates aragonite, also with some organic. The mainly mineral of ammolite is aragonite, which imbricates, as well as a small amount of calcite prism-shaped calcite distributes. The thickness of purple sample ranges from 130 nm to 160 nm, averaged 145 nm. The thickness of green sample ranges from 170 nm to210 nm, averaged 194 nm. The thickness of red sample ranges from 190 to 290 nm,averaged 232 nm. The results match for the formula derived by interference,distributed within a reasonable range. With EDS, the organic matter persists, in the shape of mucoid, and a calcium phosphate are found in specific region.The relevance between arrangement and thickness of aragonite layer and Color is high. When the color changes from violet to red, the thickness of aragonite layer increases in turn. The change regularity of thickness of aragonite with different sample fit in with derivation of interference formula.The thickness of aragonite of most samples ranges from 148 nm to 260 nm. The more good quality samples, themore organic matter is. Organics can increase the toughness of ammolite; decrease the chance of being damaged.