{"site":"https://digitalgemology.com","build":"20261101-105320","refractometer_limit":1.81,"about":"Seven gemstones only. Values are the ones Digital Gemology's tools use; a match is a lead, not an identification.","gemstones":[{"slug":"diamond","name":"Diamond","url":"https://digitalgemology.com/gemstones/diamond","crystal_system":"Cubic","optic":"singly refractive","refractive_index":{"text":"2.417","low":2.417,"high":2.417},"birefringence":0.0,"birefringence_text":"None (isotropic)","dispersion":0.044,"specific_gravity":{"text":"3.52","low":3.52,"high":3.52},"hardness_mohs":"10","critical_angle":"24.4°","refractometer":"Over the limit: 2.417 is above a standard refractometer's 1.81","polariscope":"Stays dark as it turns (singly refractive); strain can show as patchy light","pleochroism":{"strength":"None","colors":[]},"spectrum":{"element":null,"none":"Colorless diamond (the simulator's D color) absorbs nothing in the visible, so the spectrum is unbroken.","features":[]},"tools":{"refractometer":"https://digitalgemology.com/tools/refractometer","dichroscope":"https://digitalgemology.com/tools/dichroscope","spectroscope":"https://digitalgemology.com/tools/spectroscope","polariscope":"https://digitalgemology.com/tools/polariscope","simulator":"https://digitalgemology.com/tools/3d_gemstone_simulator"}},{"slug":"moissanite","name":"Moissanite","url":"https://digitalgemology.com/gemstones/moissanite","crystal_system":"Hexagonal","optic":"doubly refractive (uniaxial)","refractive_index":{"text":"2.648 to 2.691","low":2.648,"high":2.691,"omega":2.648,"epsilon":2.691},"birefringence":0.043,"birefringence_text":"0.043","dispersion":0.104,"specific_gravity":{"text":"3.22","low":3.22,"high":3.22},"hardness_mohs":"9.25","critical_angle":"22.2°","refractometer":"Over the limit: 2.648 to 2.691 is above a standard refractometer's 1.81","polariscope":"Blinks light and dark four times a turn (doubly refractive)","pleochroism":{"strength":"None visible (colorless)","colors":[]},"spectrum":{"element":null,"none":"Colorless moissanite, as in the simulator: nothing absorbed in the visible.","features":[]},"tools":{"refractometer":"https://digitalgemology.com/tools/refractometer","dichroscope":"https://digitalgemology.com/tools/dichroscope","spectroscope":"https://digitalgemology.com/tools/spectroscope","polariscope":"https://digitalgemology.com/tools/polariscope","simulator":"https://digitalgemology.com/tools/3d_gemstone_simulator"}},{"slug":"cubic-zirconia","name":"Cubic Zirconia","url":"https://digitalgemology.com/gemstones/cubic-zirconia","crystal_system":"Cubic","optic":"singly refractive","refractive_index":{"text":"2.15 to 2.18","low":2.15,"high":2.15},"birefringence":0.0,"birefringence_text":"None (isotropic)","dispersion":0.06,"specific_gravity":{"text":"5.6 to 6.0","low":5.6,"high":6.0},"hardness_mohs":"8 to 8.5","critical_angle":"27.7°","refractometer":"Over the limit: 2.15 to 2.18 is above a standard refractometer's 1.81","polariscope":"Stays dark as it turns (singly refractive); strain can show as patchy light","pleochroism":{"strength":"None","colors":[]},"spectrum":{"element":null,"none":"Colorless cubic zirconia: nothing absorbed in the visible.","features":[]},"tools":{"refractometer":"https://digitalgemology.com/tools/refractometer","dichroscope":"https://digitalgemology.com/tools/dichroscope","spectroscope":"https://digitalgemology.com/tools/spectroscope","polariscope":"https://digitalgemology.com/tools/polariscope","simulator":"https://digitalgemology.com/tools/3d_gemstone_simulator"}},{"slug":"ruby","name":"Ruby","url":"https://digitalgemology.com/gemstones/ruby","crystal_system":"Trigonal","optic":"doubly refractive (uniaxial)","refractive_index":{"text":"1.762 to 1.770","low":1.762,"high":1.77,"omega":1.77,"epsilon":1.762},"birefringence":0.008,"birefringence_text":"0.008","dispersion":0.018,"specific_gravity":{"text":"4.00","low":4.0,"high":4.0},"hardness_mohs":"9","critical_angle":"34.6°","refractometer":"Two readings, 1.762 and 1.77 (birefringence 0.008)","polariscope":"Blinks light and dark four times a turn (doubly refractive)","pleochroism":{"strength":"Strong","colors":["purplish red","orangy red"]},"spectrum":{"element":"chromium","none":null,"features":[{"kind":"line","nm":[692.8,694.2],"cause":"Cr³⁺","what":"the R lines, a close pair in the deep red"},{"kind":"line","nm":[668],"cause":"Cr³⁺","what":"a weaker line in the red"},{"kind":"line","nm":[659],"cause":"Cr³⁺","what":"a weaker line in the red"},{"kind":"band","nm":[500,610],"cause":"Cr³⁺","what":"a broad band across the yellow-green: what makes ruby red"},{"kind":"line","nm":[475.0,476.5],"cause":"Cr³⁺","what":"a pair of lines in the blue, seen as one"},{"kind":"line","nm":[468.5],"cause":"Cr³⁺","what":"a line in the blue"},{"kind":"band","nm":[400,430],"cause":"Cr³⁺","what":"the violet absorbed"}]},"tools":{"refractometer":"https://digitalgemology.com/tools/refractometer","dichroscope":"https://digitalgemology.com/tools/dichroscope","spectroscope":"https://digitalgemology.com/tools/spectroscope","polariscope":"https://digitalgemology.com/tools/polariscope","simulator":"https://digitalgemology.com/tools/3d_gemstone_simulator"}},{"slug":"sapphire","name":"Sapphire","url":"https://digitalgemology.com/gemstones/sapphire","crystal_system":"Trigonal","optic":"doubly refractive (uniaxial)","refractive_index":{"text":"1.762 to 1.770","low":1.762,"high":1.77,"omega":1.77,"epsilon":1.762},"birefringence":0.008,"birefringence_text":"0.008","dispersion":0.018,"specific_gravity":{"text":"4.00","low":4.0,"high":4.0},"hardness_mohs":"9","critical_angle":"34.6°","refractometer":"Two readings, 1.762 and 1.77 (birefringence 0.008)","polariscope":"Blinks light and dark four times a turn (doubly refractive)","pleochroism":{"strength":"Strong","colors":["violetish blue","greenish blue"]},"spectrum":{"element":"iron","none":null,"features":[{"kind":"line","nm":[450],"cause":"Fe³⁺","what":"the iron line, strongest in iron-rich stones"},{"kind":"line","nm":[460],"cause":"Fe³⁺","what":"a weak iron line"},{"kind":"line","nm":[471],"cause":"Fe³⁺","what":"a weak iron line"},{"kind":"band","nm":[540,700],"cause":"Fe²⁺–Ti⁴⁺","what":"a broad band from the yellow into the red: the blue color itself"}]},"tools":{"refractometer":"https://digitalgemology.com/tools/refractometer","dichroscope":"https://digitalgemology.com/tools/dichroscope","spectroscope":"https://digitalgemology.com/tools/spectroscope","polariscope":"https://digitalgemology.com/tools/polariscope","simulator":"https://digitalgemology.com/tools/3d_gemstone_simulator"}},{"slug":"emerald","name":"Emerald","url":"https://digitalgemology.com/gemstones/emerald","crystal_system":"Hexagonal","optic":"doubly refractive (uniaxial)","refractive_index":{"text":"1.577 to 1.583","low":1.577,"high":1.583,"omega":1.583,"epsilon":1.577},"birefringence":0.006,"birefringence_text":"0.006","dispersion":0.014,"specific_gravity":{"text":"2.72","low":2.72,"high":2.72},"hardness_mohs":"7.5 to 8","critical_angle":"39.4°","refractometer":"Two readings, 1.577 and 1.583 (birefringence 0.006)","polariscope":"Blinks light and dark four times a turn (doubly refractive)","pleochroism":{"strength":"Distinct","colors":["yellowish green","bluish green"]},"spectrum":{"element":"chromium","none":null,"features":[{"kind":"line","nm":[683.0],"cause":"Cr³⁺","what":"the stronger of the R lines in the deep red"},{"kind":"line","nm":[680.5],"cause":"Cr³⁺","what":"the other R line, beside the 683 nm line"},{"kind":"line","nm":[662],"cause":"Cr³⁺","what":"a line in the red, mostly in the e-ray"},{"kind":"line","nm":[646],"cause":"Cr³⁺","what":"a line in the red, in the e-ray"},{"kind":"line","nm":[637],"cause":"Cr³⁺","what":"a line in the orange-red, in the o-ray"},{"kind":"band","nm":[580,630],"cause":"Cr³⁺","what":"a broad band in the yellow and orange, only partly dark"},{"kind":"line","nm":[477.4],"cause":"Cr³⁺","what":"a weak line in the blue"},{"kind":"band","nm":[400,440],"cause":"Cr³⁺","what":"the violet absorbed"}]},"tools":{"refractometer":"https://digitalgemology.com/tools/refractometer","dichroscope":"https://digitalgemology.com/tools/dichroscope","spectroscope":"https://digitalgemology.com/tools/spectroscope","polariscope":"https://digitalgemology.com/tools/polariscope","simulator":"https://digitalgemology.com/tools/3d_gemstone_simulator"}},{"slug":"amethyst","name":"Amethyst","url":"https://digitalgemology.com/gemstones/amethyst","crystal_system":"Trigonal","optic":"doubly refractive (uniaxial)","refractive_index":{"text":"1.544 to 1.553","low":1.544,"high":1.553,"omega":1.544,"epsilon":1.553},"birefringence":0.009,"birefringence_text":"0.009","dispersion":0.013,"specific_gravity":{"text":"2.65","low":2.65,"high":2.65},"hardness_mohs":"7","critical_angle":"40.4°","refractometer":"Two readings, 1.544 and 1.553 (birefringence 0.009)","polariscope":"Blinks light and dark four times a turn (doubly refractive)","pleochroism":{"strength":"Weak to moderate","colors":["bluish purple","reddish purple"]},"spectrum":{"element":null,"none":null,"features":[{"kind":"band","nm":[500,600],"cause":"iron color center","what":"a weak broad band in the yellow-green, and no lines"}]},"tools":{"refractometer":"https://digitalgemology.com/tools/refractometer","dichroscope":"https://digitalgemology.com/tools/dichroscope","spectroscope":"https://digitalgemology.com/tools/spectroscope","polariscope":"https://digitalgemology.com/tools/polariscope","simulator":"https://digitalgemology.com/tools/3d_gemstone_simulator"}}]}