The Tycoon Cut™ was invented in 1999 by Toros Kejejian . The name Tycoon Cut is trademarked, and has been patented in both the US and internationally. Los Angles based Tycoon Jewelry is its sole distributor.
The cut is a rectangular mixed cut. It has 33 facets—nine on the crown and 24 making up the pavilion. The faceting of the crown is what makes the Tycoon Cut unique as the entire crown can be considered a nine facet table. The top center facet is in the shape of a diamond, making it the only diamond with a diamond on top.
Thursday, January 11, 2007
How To Judge Alexandrite (color change) Chrysoberyl
Color
- The primary consideration is the extent of color change. The most desirable color change is saturated ruby red (incandescent lighting) to saturated emerald green (day light or fluorescent light). Quite often the stones have color modifiers which may result in the reds having a purplish, and the greens a bluish secondary color.
- In most cases the saturation level of both hues is relatively low so stones that show colors of high intensity fetch higher premium.
Phenomenon
- The stone should display distinct change of color from an incandescent light source to a day light fluorescent one.
Clarity
- The clarity of the stone is a factor. Alexandrites may be heavily included; as long as the inclusions are not too distracting, the stone should be judged based on the unique color change.
Cut
- Alexandrites are usually faceted. If they a show a chatoyant phenomenon, they may be cut cabochon.
- The primary consideration is the extent of color change. The most desirable color change is saturated ruby red (incandescent lighting) to saturated emerald green (day light or fluorescent light). Quite often the stones have color modifiers which may result in the reds having a purplish, and the greens a bluish secondary color.
- In most cases the saturation level of both hues is relatively low so stones that show colors of high intensity fetch higher premium.
Phenomenon
- The stone should display distinct change of color from an incandescent light source to a day light fluorescent one.
Clarity
- The clarity of the stone is a factor. Alexandrites may be heavily included; as long as the inclusions are not too distracting, the stone should be judged based on the unique color change.
Cut
- Alexandrites are usually faceted. If they a show a chatoyant phenomenon, they may be cut cabochon.
Fiber Optic Technology
David R. Goff writes:
A Brief History of Fiber Optic Technology
Fiber optic technology experienced a phenomenal rate of progress in the second half of the twentieth century. Early success came during the 1950’s with the development of the fiberscope. This image-transmitting device, which used the first practical all-glass fiber, was concurrently devised by Brian O’Brien at the American Optical Company and Narinder Kapany (who first coined the term “fiber optics” in 1956) and colleagues at the Imperial College of Science and Technology in London. Early all-glass fibers experienced excessive optical loss, the loss of the light signal as it traveled the fiber, limiting transmission distances.
More info @ http://www.fiber-optics.info/fiber-history.htm
A Brief History of Fiber Optic Technology
Fiber optic technology experienced a phenomenal rate of progress in the second half of the twentieth century. Early success came during the 1950’s with the development of the fiberscope. This image-transmitting device, which used the first practical all-glass fiber, was concurrently devised by Brian O’Brien at the American Optical Company and Narinder Kapany (who first coined the term “fiber optics” in 1956) and colleagues at the Imperial College of Science and Technology in London. Early all-glass fibers experienced excessive optical loss, the loss of the light signal as it traveled the fiber, limiting transmission distances.
More info @ http://www.fiber-optics.info/fiber-history.htm
Raman Spectroscopy
Renishaw writes:
Users in research laboratories, development labs and production lines worldwide employ the microscopes and analysers in a diverse range of fields - for example, in the computer hard disc, pharmaceutical, polymer, semiconductor, and chemical industries. More exotic applications include the identification of drugs and explosives by forensic scientists, and the analysis of paint and pigments on historic works of art as an aid to accurate restoration.
Gemmologists are also using the Raman microscopes to identify gemstones, and to determine their source by analysing the tiny mineral inclusions contained within them.
Currently, there is much discussion in the gems community about a new heat-treatment for poor quality diamonds that changes their appearance to that of gem quality diamond. Fortunately, Renishaw Raman systems can reveal when this has occurred, ensuring that true diamond quality is maintained. Also, a variety of medical applications is being developed, one of the most notable being the detection of cancerous and pre-cancerous cells. In the near future, it is expected that small optical fibre probes and automated microscope systems will be used to acquire spectra from human tissue, allowing the rapid diagnosis of potential cancers as an outpatient procedure.
The capabilities of the instruments have been expanded to include a wider range of lasers, enhanced optical filtering systems, many new accessories, increased automation and improved software, making the instruments even easier to use. The number of applications will increase as Renishaw continues to develop new technologies in Raman spectroscopy.
More info @ http://www.renishaw.com/client/product/UKEnglish/PGP-37.shtml
Users in research laboratories, development labs and production lines worldwide employ the microscopes and analysers in a diverse range of fields - for example, in the computer hard disc, pharmaceutical, polymer, semiconductor, and chemical industries. More exotic applications include the identification of drugs and explosives by forensic scientists, and the analysis of paint and pigments on historic works of art as an aid to accurate restoration.
Gemmologists are also using the Raman microscopes to identify gemstones, and to determine their source by analysing the tiny mineral inclusions contained within them.
Currently, there is much discussion in the gems community about a new heat-treatment for poor quality diamonds that changes their appearance to that of gem quality diamond. Fortunately, Renishaw Raman systems can reveal when this has occurred, ensuring that true diamond quality is maintained. Also, a variety of medical applications is being developed, one of the most notable being the detection of cancerous and pre-cancerous cells. In the near future, it is expected that small optical fibre probes and automated microscope systems will be used to acquire spectra from human tissue, allowing the rapid diagnosis of potential cancers as an outpatient procedure.
The capabilities of the instruments have been expanded to include a wider range of lasers, enhanced optical filtering systems, many new accessories, increased automation and improved software, making the instruments even easier to use. The number of applications will increase as Renishaw continues to develop new technologies in Raman spectroscopy.
More info @ http://www.renishaw.com/client/product/UKEnglish/PGP-37.shtml
Wednesday, January 10, 2007
Bernd Munsteiner
Probably the most exciting development in gem cutting since the creation of the round brilliant is a style of gem cutting developed in the 1970's by Idar-Oberstein artist-craftsman extraordinaire, Bernd Munsteiner.
Today, Munsteiner's work has been widely copied and even mass produced. The generic style is known variously as the Munsteiner or Fantasy Cut. Stones display facets, but rather than being flat, they are arranged in v-shaped grooves somewhat similar to the striations on certain crystals. Combinations of flat facets and curved surfaces are also sometimes seen.
To know more about the Master cutter and jewelry designer, visit the following websites at:
www.khulsey.com/jewelry/atelier_munsteiner.html
www.munsteiner-cut.de
Today, Munsteiner's work has been widely copied and even mass produced. The generic style is known variously as the Munsteiner or Fantasy Cut. Stones display facets, but rather than being flat, they are arranged in v-shaped grooves somewhat similar to the striations on certain crystals. Combinations of flat facets and curved surfaces are also sometimes seen.
To know more about the Master cutter and jewelry designer, visit the following websites at:
www.khulsey.com/jewelry/atelier_munsteiner.html
www.munsteiner-cut.de
How To Judge Opal
Color
First of all, define the type of opal (black, semi-black, crystal, white, etc.) you are evaluating.
Questions to ask regarding color:
- Play-of-color and pattern of color (if applicable). What are the predominant colors? Reds, violets and oranges are more valuable than greens and blues. Red is the rarest, and if present, all other colors are possible. If blue is visible face-up, then other colors will not be possible. Also take into account the distribution, contrast and abundance of colors present.
- Grading opal patterns is quite subjective and may depend largely of the viewer's personal taste. Generally the more colors that appear to the viewer the more valuable the stone. Stones showing largely blue flash are least valuable.
-Pinfire, consisting of small dots of color is quite common, and not especially valuable, even if the predominant color is red.
-Flash refers to opals with color patterns that appear suddenly as the stone is moved.
-Harlequin refers to opals with a regular arrangement of similarly-sized flashes of color. The more regular the arrangement, the better. Stones showing the full range of colors in this pattern are exceedingly rare and valuable.
- Extinction : Does the full color range appear over a small viewing angle?
- In other words, is there an angle of extinction, during a 360x rotation, no colors are visible? Another way of describing this is directionality - the most valuable stones do not show any extinction of color.
- Brilliancy : How intense are the colors? Do they stand out from the background? How is the color distributed?
- Consider the amount of potch in comparison with the amount of play-of-color. Although potch provides a background for the play-of-color, we buy opal per carat, and so do not want to purchase opals with excessive amounts of potch (potch to play-of-color ratio).
- Sequence of colors : Red that holds over a wide range of viewing angles is the most desirable. In black opal, a red immediately followed by a royal blue is the rarest and most sought-after color sequence.
Practical Tip: Place the opal on a flat surface at arm's length; then rotate it through 360˚ noting the play-of-color, brilliance, and intensity of colors, symmetry and polish. Then hold the opal up to the light and estimate the ratio of potch to play-of-color.
Fine opals should show:
- Uniform play-of-color through 360º
- Intense, brilliant colors
- No 'extinction'
- Symmetrical cut, and fine degree of polish
Judge other opals from this ideal standpoint.
Clarity
Note the following:
- How transparent is the material? High transparency is sought after in light opal, but may reduce the value of black opal.
- Are any fragments of matrix present? Potch, fragments of host rock, sand or other impurities should not interrupt the play-of-color. Material should be free from blemishes visible from top.
- Are there any cracks and flaws visible? Precious opal can contain around 6-10% water and some opals from certain areas may craze, crack and/or turn opaque. Remember, never buy a cracked opal. The crack will only get worse as time passes.
Cut
In judging cut, look for the symmetry (proportions) and polish (finish). Is the make (cut and proportions) of the cabochon good? How good is the surface polish?
First of all, define the type of opal (black, semi-black, crystal, white, etc.) you are evaluating.
Questions to ask regarding color:
- Play-of-color and pattern of color (if applicable). What are the predominant colors? Reds, violets and oranges are more valuable than greens and blues. Red is the rarest, and if present, all other colors are possible. If blue is visible face-up, then other colors will not be possible. Also take into account the distribution, contrast and abundance of colors present.
- Grading opal patterns is quite subjective and may depend largely of the viewer's personal taste. Generally the more colors that appear to the viewer the more valuable the stone. Stones showing largely blue flash are least valuable.
-Pinfire, consisting of small dots of color is quite common, and not especially valuable, even if the predominant color is red.
-Flash refers to opals with color patterns that appear suddenly as the stone is moved.
-Harlequin refers to opals with a regular arrangement of similarly-sized flashes of color. The more regular the arrangement, the better. Stones showing the full range of colors in this pattern are exceedingly rare and valuable.
- Extinction : Does the full color range appear over a small viewing angle?
- In other words, is there an angle of extinction, during a 360x rotation, no colors are visible? Another way of describing this is directionality - the most valuable stones do not show any extinction of color.
- Brilliancy : How intense are the colors? Do they stand out from the background? How is the color distributed?
- Consider the amount of potch in comparison with the amount of play-of-color. Although potch provides a background for the play-of-color, we buy opal per carat, and so do not want to purchase opals with excessive amounts of potch (potch to play-of-color ratio).
- Sequence of colors : Red that holds over a wide range of viewing angles is the most desirable. In black opal, a red immediately followed by a royal blue is the rarest and most sought-after color sequence.
Practical Tip: Place the opal on a flat surface at arm's length; then rotate it through 360˚ noting the play-of-color, brilliance, and intensity of colors, symmetry and polish. Then hold the opal up to the light and estimate the ratio of potch to play-of-color.
Fine opals should show:
- Uniform play-of-color through 360º
- Intense, brilliant colors
- No 'extinction'
- Symmetrical cut, and fine degree of polish
Judge other opals from this ideal standpoint.
Clarity
Note the following:
- How transparent is the material? High transparency is sought after in light opal, but may reduce the value of black opal.
- Are any fragments of matrix present? Potch, fragments of host rock, sand or other impurities should not interrupt the play-of-color. Material should be free from blemishes visible from top.
- Are there any cracks and flaws visible? Precious opal can contain around 6-10% water and some opals from certain areas may craze, crack and/or turn opaque. Remember, never buy a cracked opal. The crack will only get worse as time passes.
Cut
In judging cut, look for the symmetry (proportions) and polish (finish). Is the make (cut and proportions) of the cabochon good? How good is the surface polish?
Tuesday, January 09, 2007
Refractometer
The instrument in general use for the measurement of refractive index is the refractometer. The refractometer determines the refractive index of a gemstone by using the principle of critical angle of total internal reflection, which is used to measure the refractive indices of various substances.
General information
- Refractive Index (RI) measurement is the most useful and accurate means of testing gemstones.
- It is convenient, non-destructive and relatively quick to carry out providing useful information.
Requirements
- Optical contact.
- Clean, polished surface.
- Contact liquid.
- Refractive index (RI) of the stone under test should be within the range of the instrument.
Limits
- Upper limit of the refractometer is determined by the refractive index of the prism as well as the refractive index of the contact fluid / medium.
- In a normal commercial refractometer, this is 1.81 (some RI liquids may have a limit of 1.79).
Results
- Flat surface readings: single refractive (SR) / double refractive (DR), birefringence, optic character (uniaxial or biaxial), and optic sign (positive or negative).
- Curved surface readings (distant vision method): Mean refractive index only.
General information
- Refractive Index (RI) measurement is the most useful and accurate means of testing gemstones.
- It is convenient, non-destructive and relatively quick to carry out providing useful information.
Requirements
- Optical contact.
- Clean, polished surface.
- Contact liquid.
- Refractive index (RI) of the stone under test should be within the range of the instrument.
Limits
- Upper limit of the refractometer is determined by the refractive index of the prism as well as the refractive index of the contact fluid / medium.
- In a normal commercial refractometer, this is 1.81 (some RI liquids may have a limit of 1.79).
Results
- Flat surface readings: single refractive (SR) / double refractive (DR), birefringence, optic character (uniaxial or biaxial), and optic sign (positive or negative).
- Curved surface readings (distant vision method): Mean refractive index only.
Diamond Cut: STARBURST
The Starburst Cut name is a patent of Louis Glick & Co and U Doppelt & Co, developed 25 years ago by the Louis Glick and U Doppelt companies.
The Starburst is a modified radiant cut. It is a rectangular brilliant cut with 88 or more kite and star shaped facets. Often there are twice as many facets on a Starburst as on a traditional round cut.
The Starburst is a modified radiant cut. It is a rectangular brilliant cut with 88 or more kite and star shaped facets. Often there are twice as many facets on a Starburst as on a traditional round cut.
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