Desktop polarizer FTP-49

Desktop polarizer Model: FTP-49 Instrument: polarizer is mainly used to distinguish between homogeneous and heterogeneous gem stones and crystal (crypto-crystalline or microcrystalline) aggregates, abnormal birefringence gem identification. Under certain circumstances, with conoscope can be observed interference pattern gem determine axial gem. Large Diameter 49mm polarizer; rotating stage, 3600 rotatably; with the cone of light a lens for viewing the non-homogeneous gem interferogram; long-life white LED cold light source, is more conducive to the protection of the polarizer; bulbs: high brightness, long-life LED white light bulbs; with wide voltage DC3V external power supply; power supply: 220V-240V, 50-60HZ; * 49mm large-caliber polarizer; * rotating stage; * with a large-diameter cone of light a lens for viewing the non-homogeneous Gem interference pattern; * With wide voltage DC3V external power supply. Third, steps 1, wipe the stones, turn the light source 2, adjust the polarizing plate to the lower polarizing plate orthogonal (sight dark) 3, the jewel placed in a glass on a stage rotate 360 ??degrees from the polarizing Observation gem shade above the sheet 4, if the birefringent material (one rotation of four out four dark), find the ball with the optical axis of the interference observed interference pattern, four fixed axis, explain a phenomenon, phenomenon: four out four dark under crossed polarizers rotating gems week, four out four dark change occurs Conclusions: Non-axis direction heterogeneous body gemstones, crystal, red Sapphire, etc. 2, all dark (extinction) orthogonal polarized light is rotated 360 degrees gem, no light through the whole dark conclusion: the optical axis homogeneous or heterogeneous body body gems, such as garnet, spinel, glass, etc. Special Note: Non-homogeneous body axis direction appears to interfere in Figure 3, the collective Under extinction orthogonal polarized, rotating gem a week, always bright conclusion: polycrystalline aggregates gem heterogeneous body, such as agate, jade, quartz rock and other reasons: (1) the aggregate translucent gem - nearly transparent, Masamitsu microscope The total extinction position is not part of the particles, and thus the total light transmittance, the overall brighter (2) grain boundary effects produce bright light will pass through Special Note: Due to the non-homogeneous body fractured gem, there will be a mirror phenomenon such as emeralds, rubies common 4, several special phenomena (1) Exception Extinction: homogeneous body gem due to stress in uneven extinction phenomenon orthogonal polarizing microscope show common: 1) markings, wavy, plaid like, snake-like: synthetic spinel common 2) False Cross Extinction: common in glass, plastic and other synthetic materials Conclusion: The method homogeneous body gem abnormal extinction: the upper and lower polarizing film is a gem orthogonal Go The brightest, fast rotating polarizer, if the gem brighter, was an exception extinction, does not change birefringent extinction (2) all dark illusion of some high-refractive gem: zircon, rutile, countertops placed down When almost no light through total reflection occurs all dark phenomenon Workaround: You can select different facets placement, combined with other instruments decision (3) full light phenomenon: the development of crack special gems (emeralds, rubies common) V. interference observed in Figure 1, the principle: the light in a non-homogeneous body gem in dissemination, birefringence, broken down into two mutually perpendicular polarization direction of vibration, two different RI (propagation speed different) cause a certain optical path difference, After converging cone of light interfere role, and an interference Figure 2, the phenomenon: 1) a crystal axis interferogram: Black Cross plus interference color ring 2) two-axis crystal interference pattern: a curved single (double) arm + interference color ring 3) bovine interference pattern (interference color hollow cross and circle): Rock Crystals (endemic) 4) propeller-like interference pattern: some amethyst (with complex twin crystals, synthetic generally do not) 3, observation method 1) For vertically polarized quadrature position 2) full-rotation axis direction to find gems (interference color appeared approach) 3) in the direction of the most intensive interference colors plus interference ball observation 4) interfere with balls positioned between the polarizing plate and precious stones Special Note: interference pattern appears only in a non-homogeneous body transparent single crystal gem sixth, use 1, to determine the optical characteristics of the stone (homogeneous body, a non-homogeneous body, abnormal birefringence, collective extinction) 2, determine the gem's axis of (a crystal axis, two-axis crystal): 3 in favor of interference ball, observe multicolor gems: the use of polarized light (vertical Polaroid parallel), turn gemstone color change was observed seven or eight considerations for transparent - translucent Gem (poor transparency gem conclusions unreliable) 9, observed from at least three directions (the optical axis direction and avoid total reflection) ten, crack, crack science, twins, inclusion of more gem effect on the conclusions of eleven The sample is too small or abnormal sample extinction, in conjunction with other instruments for verification twelve, watch black cross abnormal extinction and a crystal axis difference interferogram