- #Yellow amethyst vs heat treated amethyst professional
- #Yellow amethyst vs heat treated amethyst free
In order to obtain and analyze the color of minerals, the color grading method of colored diamond was proposed in 1994 18. The main absorption bands of amethyst in UV–Vis spectra are located at 950 nm, 540 nm and 360 nm, which is considered to be related to the transition of Fe 4+ in tetrahedral coordination 9, 12, 16, 17, and these absorption bands show different degrees of changes after irradiation or heating. The study of UV–visible spectroscopy of amethyst also provides support for the study of the existing form of iron element in amethyst. The color change of amethyst after heating and irradiation is related to the “color center activated by iron” 7, 15. Amethyst could become citrine when the temperature is over 500 ☌ 10, and the violet and green color could be appeared by irradiating the colorless quartz 14.
Many scholars have studied the enhancement methods of amethyst to discuss the mechanism of the coloration 7, 13, 14. In addition, holes created during quartz irradiation can also act as charge compensators 12. It was postulated that amethyst color can be related to the replacing Si 4+ with Fe 3+, and alkali metal ions (Li +, Na + or H +) are introduced to maintain the charge balance 11.
The colors of amethyst 6, 7, citrine 8 and prasiolite 7, 9, 10 are all related to iron. When the quartz contains impurities such as iron, aluminum and titanium, it will make quartz appear rich in color 5. It is widely distributed in the crust and the origins are all over the world, such as Brazil, Uruguay, Canada, Sri Lanka 1, Rwanda 2, Morocco 3 and Arizona 4, etc. A more appropriate heating temperature to obtain citrine by heating amethyst is about 560 ☌.Īmethyst is a kind of α-quartz with beautiful violet color. When the initial color is darker, the color difference of heated amethyst is larger, and the easier it is to change the color after heat treatment. The color change degree of heated amethyst is related to its initial color. The color at different temperatures can be divided into three stages: The amethyst stage with temperature below 420 ☌, the prasiolite stage with temperature between 420 and 440 ☌ where the color center is the most unstable, the citrine stage with temperature above 440 ☌. The absorption band at 545 nm in the UV–visible spectrum can be related to a charge-transfer transition of Fe 3+ and O 2−, which has a significant relationship with amethyst lightness and chroma. The results show that the amethyst color has no significant relationship with cell parameters but the crystallinity index decreases as temperature rises. Gemological laboratories can also provide certification for your citrine, confirming its authenticity and providing additional information about its origin, treatment, and quality.The effect of heat treatment on amethyst color was studied from a new perspective of chromaticity of gemstones and the cause of amethyst coloration was discussed based on the results of X-ray diffraction, ultraviolet–visible spectroscopy. They have the expertise and equipment to accurately assess the gemstone.
#Yellow amethyst vs heat treated amethyst professional
To confirm the authenticity of your citrine, consult a professional gemologist or a reputable jeweler. Natural citrine is usually lighter in color. If you see colors that are a darker yellow/orange, then it’s likely that it’s a heated amethyst instead of natural citrine. If you see any bubbles in the piece, that piece is glass as natural citrine won’t have any.Ĭolors: Heat-treated amethyst often shows colors that are more intense color at the tips of the crystals and fading toward the base.
#Yellow amethyst vs heat treated amethyst free
Magnification: Under magnification, natural citrine may reveal inclusions or growth patterns, while glass will appear more uniform and free of flaws.A refractometer can help measure this property, but this test is usually conducted by a professional gemologist. Refractive Index: Real citrine has a refractive index of 1.54-1.55, while glass typically ranges from 1.45-1.50.A scratch test can help differentiate them, but it's not recommended as it can damage the gemstone. Scratch Test: Citrine has a Mohs hardness of 7, while glass is generally around 5.5.Glass beads that are imitations of amethyst, citrine and ametrineĭifferentiating Real Citrine from Imitations Real Citrine vs.
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