Emerald Unpolarised - Green Gem Spectrum
EMERALD (Unpolarised) Color mainly due to chromium. As this spectrum incorporates both the ordinary and extraordinary rays several features of each are seen. As in most chromium spectra not much transmission is seen below 465nm. The broad absorption band in the yellowish green to orange will vary in strength and width according to the depth of color of the stone. Two other main features are a moderate narrow band at 637nm. and the usual chromium doublet, this time at 680nm. and 683nm. This is a strong spectrum from a Colombian emerald and paler stones show a weaker absorption pattern. Vanadium may be present and contribute a little to the absorption.
Emerald ω ray - Green Gem Spectrum
EMERALD (ω-ray) When the yellowish-green o ray isolated by a polarising filter the line at 637nm. is seen to strengthen and the doublet in the red appears a little weaker. The broad absorption band is more intense and in a good saturated color as we have here another line due to the high chromium content appears at 477nm. in the blue. This is only seen in the o ray.
Emerald ε ray - Green Gem Spectrum
EMERALD (ε-ray) Two distinctive features of the bluish-green e ray are the widening of the broad central absorption band towards the long wave end where it obscures the line at 637nm. and also the darker doublet in the red which is mainly due to the much stronger line at 683nm. In stones where the central band is less intense two more fainter lines appear in the e ray at 646nm. and 662 nm. but here they are hidden in the broad absorption .
Emerald Lennix Flux Synthetic Unpolarised - Green Gem Spectrum
EMERALD LENNIX SYNTHETIC (Unpolarised) color mainly due to chromium. The spectra of synthetic emeralds are in most cases almost identical to that of the natural gemstone with variations mainly in the strength of absorption depending on the color saturation. A Lennix synthetic having a fairly high chromium content shows a spectrum similar to a natural emerald with an overall slightly stronger absorption in the synthetic.
Emerald Lennix Flux Synthetic ω ray - Green Gem Spectrum
EMERALD LENNIX SYNTHETIC (ω-ray) The o ray spectrum is typical of most emeralds of this color saturation with the feature of the line in the blue at 477nm. although in this case a little difficult to detect as absorption sets in around this point. The line in the orange- red at 637nm. has strengthened and the doublet is weaker as the o ray assumes it's more yellowish green color.
Emerald Lennix Flux Synthetic ε ray - Green Gem Spectrum
EMERALD LENNIX SYNTHETIC (ε-ray) The line at 637nm. has now disappeared, covered by the main absorption band which has moved further to the long wave side. Unlike the Colombian emerald this is slightly less intense allowing the line at 662nm. to be seen. The line sometimes seen at 646 nm. remains hidden by the main band. The shift in absorption and the absence of the line in the blue accounts for the more bluish green of the e ray.
Emerald Gilson Flux Synthetic Unpolarised - Green Gem Spectrum
EMERALD GILSON SYNTHETIC (Unpolarised) Color mainly due to chromium. As the color saturation becomes less so also does the strength of absorption . Compare this unpolarised version of both stone and spectrum to the two emeralds above and see how the spectrum is affected by the body color of this Gilson synthetic stone. The main feature of the central absorption band is weaker and narrower and the other lines are noticeably weaker.
Emerald Gilson Flux Synthetic ω ray - Green Gem Spectrum
EMERALD GILSON SYNTHETIC (ω-ray) The dichroism in this stone is more pronounced as the o ray assumes it's more yellowish green color. The o ray spectrum is typical of most emeralds of this color saturation with the feature of the line in the blue at 477nm. but rather weak and not easily detected. The central area of absorption has strengthened and widened but not to the extent of the two emeralds above. Other lines are again weaker.
Emerald Gilson Flux Synthetic ε ray - Green Gem Spectrum
EMERALD GILSON SYNTHETIC (ε-ray) As the e ray is isolated the more bluish green color is seen in the body color of the stone and the spectrum reacts accordingly. The main absorption band has moved to further to the long wave side to obscure the line at 637nm. The line at 662nm. and the doublet at 680/683nm. are present but not as strong as in deeper colored emeralds. The line in the blue at 477nm. is not present on this ray.
Emerald Biron Hydrothermal Synthetic Unpolarised - Bluish Green Gem Spectrum
EMERALD BIRON SYNTHETIC (Unpolarised) color mainly due to chromium. The intense bluish green color of this synthetic emerald provides the classic spectrum associated with an emerald rich in chromium. The general absorption in the violet and the broad central absorption band are the two immediate features which suggest emerald in a green stone of this hue. Add the strong doublet in the red a 680/683nm. and this, supported by other tests should help to identify it as natural or synthetic emerald. As the transmission in the red indicates, this stone shows red with a Chelsea filter.
Emerald Biron Hydrothermal Synthetic (ω ray) - Bluish Green Gem Spectrum
EMERALD BIRON SYNTHETIC (ω-ray) As a polarising filter picks up the greener o ray the central absorption band becomes narrower which allows the absorption line at 637nm. to become visible. The doublet in the red has become weaker and a new feature is seen as a fairly sharp line at 477nm. just before total absorption sets in at the deep blue.
Emerald Biron Hydrothermal Synthetic ε ray - Bluish Green Gem Spectrum
EMERALD BIRON SYNTHETIC ( ε-ray) Isolating the e ray causes the stone to appear even more of a bluish green. This is reflected in the spectrum by a wider transmission in the blue and the absence of the line at 477nm. which is carried by the o ray. The central band broadens to hide the line at 637nm. However a stronger narrow band appears at 644nm. and another at 662nm. with a weaker and narrower on at 673nm. The doublet at 680/683 has now become much stronger. The strength of absorption in an emerald of this color is an indication that it may be synthetic but may be seen some in natural emeralds of a fine saturated green as in GNF0764 in GN1.
Emerald Russian Hydrothermal Synthetic Unpolarised - Bluish Green Gem Spectrum
EMERALD RUSSIAN (Early type) SYNTHETIC (Unpolarised) color due to iron, nickel and chromium. The gem image shows a piece of rough material in which you can see the seed plate on which it was grown. The spectrum varies considerably from other synthetic emeralds which owe their color to mainly chromium and vanadium. There is greater transmission in the violet in which faint bands are seen at 427nm. and 440nm. due to the high iron content. The central absorption band and the narrower bands in the orange associated with chromium are weak but the fairly strong doublet at 680/683 is present. The vague absorption about 600nm. due to nickel is best seen in the e ray below. This material appears a greyish green under the Chelsea filter.
Emerald Russian Hydrothermal Synthetic ω ray - Bluish Green Gem Spectrum
EMERALD RUSSIAN (Early type) SYNTHETIC (ω-ray) Dichroism is strong, the o ray becoming a more yellowish green. The spectrum is similar to above but with less absorption in the orange and a weaker doublet in the red. However another strong absorption band appears in the deep blue at 460nm. indicating a high iron content. The weak absorption at 600nm. again is due to nickel.
Emerald Russian Hydrothermal Synthetic ε ray - Bluish Green Gem Spectrum
EMERALD RUSSIAN (Early type) SYNTHETIC ( ε-ray) In the strongly bluish green e-ray the band at 460nm. Is absent, those in the orange and the doublet in the deep red have all strengthened. The central absorption has become weak and diffuse but the two lines due to nickel are more clearly resolved at 595nm. and 605nm. to give a good indication of this type of Russian hydrothermally grown synthetic emerald.
Emerald Unpolarised - Bluish Green Gem Spectrum
EMERALD (Unpolarised) color due to chromium and vanadium. This emerald reputed to be from India has the typical bluish overtone associated with emeralds from this locality including Pakistan. The central absorption and other bands in the orange are weak and diffuse with strong absorption in the red obscuring any further lines. With such a low chromium content this emerald remains green through the Chelsea filter.
Emerald ω ray - Bluish Green Gem Spectrum
EMERALD (ω-ray) The o ray is a paler shade of green and the spectrum becomes generally weaker and diffuse with no sign of the line at 477nm. which is present in emeralds richer in chromium.
Emerald ε ray - Bluish Green Gem Spectrum
EMERALD ( ε-ray) The darker and more bluish e ray transmits very little red light and the spectrum displays only two broad moderate diffuse bands centred at 575nm. and 600nm. This again explains the cause of a green response to the Chelsea filter.