Sunday, August 12, 2007
For Immediate Sale: Exclusive Purchasing Rights Of Attractive Diamond Production
Chaim Even-Zohar writes about the most important event in the world for exploration – bringing together global participants to learn and share new technologies and exploration methods, business trends, investment issues, geology, international opportunities and exploration successes + other viewpoints @ http://www.idexonline.com/portal_FullEditorial.asp?TextSearch=&KeyMatch=0&id=25365
The Determination Of The Weight Of A Set Stone By Hydrostatic Weighing
2007: I tried it; it works.
(via The Australian Gemmologist, Vol.18, No.5, February 1993) R K Mitchell writes:
Another gemological tip arising from our earlier discussion of hydrostatic weighing is the fact that it is by no means a waste of time to do a hydrostatic on a stone in a mount. How often are we called upon to estimate the weight of set stone for insurance purposes or with a view to buying it in over the counter? Various methods have been advocated from plain guesswork, to gauges of greater or lesser efficiency, to comparison with stones of a known weight, to weighing another mount to get somewhere near the weight of the one in question, or even to measuring the stone in all its dimensions and working out a weight using complicated mathematical formulae to obtain an approximation. Some of these might work, but there is a risk of getting hopelessly wrong answers to what should be simple enough question even when we cannot get permission to unset and weigh the stone separately.
In the past I have been offered a peridot ring with the remark that it ‘must weigh over 12 carats’ and have found myself in possession of a nice stone of over 26 carats. A star sapphire offered at ‘about 15 carats’ estimated weight, turned out to be around 35 carats when I took it out of its setting. Such inexact guesses are quite unnecessary and are very dangerous to the jeweler if he is valuing the stone. The answer lies in doing an ordinary hydrostatic weighing, a matter of a few minutes only.
Simply weigh the whole item in air and then weigh it again in water. Subtract the second weight from the first to find the total loss of weight.
Then, if we already know what the stone is (from its RI) and the nature and quality of the metal (hallmark), it is very easy to arrive at a weight for either the stone or for the mount by simple calculation. First assume that the whole ring is composed of stone and multiply the stone’s SG by the loss of weight. Deduct this figure from the total weight of the piece and that will give us the extra weight due to the greater density of the metal used. Divide this figure by the known SG of the metal less the SG of the stone.
Specific gravity of precious metals
Yellow gold
9 ct=11.2
14 ct= 14.1
18 ct= 15.5
White gold
9 ct= 12.0
14 ct= 12.9
18 ct = 16.1
Platinum = 21.4
Silver = 10.3
Victorian gold mounts with silver settings are usually 15 ct gold, so an SG figure of 12 would be a fair approximation, but the method is a little less accurate with such mounts.
This gives us the loss of weight due to the mount alone. Subtract this from the total loss of weight to find the loss due to the stone only, and multiply the result by the SG of the stone. This sounds complicated, but it is nothing of the kind. Try it and see. The longest part is the weighing and even that should not take more than a few minutes.
To give you an actual example:
An aquamarine (SG=2.70) and 18ct gold (SG=15.5) ring weighs 35.32 cts.
In water it weighs 28.75 carats
Loss of weight = 6.57 carats
If all aquamarine then weight would be 6.57 x 2.70 = 17.74
Extra weight due to gold = 35.52 – 17.74 = 17.58.
So loss of weight of mount is 17.58 divided by 15.5 – 2.7 = 1.37.
So loss of weight due to the stone is 6.57 – 1.37 = 5.20.
Weight of the stone is then 5.20 x 2.70 = 14.04 carats.
There are very minor differences in the SG of a gem species from stone to stone, and rather greater differences in the SG of gold of a given caratage (bullion dealers for this reason usually quote only to one place of decimals). But this method can usually be relied upon to give an answer well within 10% of the true weight of a stone. Where there are a few small diamonds included in the design one obviously needs to take these into account at the end of the main calculation by deducting say half a carat from the estimated weight of the main stone. Most jewelers are expert at estimating the weight of small diamonds by sight and should have little difficulty in making a reasonable correction for this situation. The method only really comes to grief when a mass of large stones of mixed species are found in one mount, and even then some guidance can be obtained from the exercise if it is used intelligently.
(via The Australian Gemmologist, Vol.18, No.5, February 1993) R K Mitchell writes:
Another gemological tip arising from our earlier discussion of hydrostatic weighing is the fact that it is by no means a waste of time to do a hydrostatic on a stone in a mount. How often are we called upon to estimate the weight of set stone for insurance purposes or with a view to buying it in over the counter? Various methods have been advocated from plain guesswork, to gauges of greater or lesser efficiency, to comparison with stones of a known weight, to weighing another mount to get somewhere near the weight of the one in question, or even to measuring the stone in all its dimensions and working out a weight using complicated mathematical formulae to obtain an approximation. Some of these might work, but there is a risk of getting hopelessly wrong answers to what should be simple enough question even when we cannot get permission to unset and weigh the stone separately.
In the past I have been offered a peridot ring with the remark that it ‘must weigh over 12 carats’ and have found myself in possession of a nice stone of over 26 carats. A star sapphire offered at ‘about 15 carats’ estimated weight, turned out to be around 35 carats when I took it out of its setting. Such inexact guesses are quite unnecessary and are very dangerous to the jeweler if he is valuing the stone. The answer lies in doing an ordinary hydrostatic weighing, a matter of a few minutes only.
Simply weigh the whole item in air and then weigh it again in water. Subtract the second weight from the first to find the total loss of weight.
Then, if we already know what the stone is (from its RI) and the nature and quality of the metal (hallmark), it is very easy to arrive at a weight for either the stone or for the mount by simple calculation. First assume that the whole ring is composed of stone and multiply the stone’s SG by the loss of weight. Deduct this figure from the total weight of the piece and that will give us the extra weight due to the greater density of the metal used. Divide this figure by the known SG of the metal less the SG of the stone.
Specific gravity of precious metals
Yellow gold
9 ct=11.2
14 ct= 14.1
18 ct= 15.5
White gold
9 ct= 12.0
14 ct= 12.9
18 ct = 16.1
Platinum = 21.4
Silver = 10.3
Victorian gold mounts with silver settings are usually 15 ct gold, so an SG figure of 12 would be a fair approximation, but the method is a little less accurate with such mounts.
This gives us the loss of weight due to the mount alone. Subtract this from the total loss of weight to find the loss due to the stone only, and multiply the result by the SG of the stone. This sounds complicated, but it is nothing of the kind. Try it and see. The longest part is the weighing and even that should not take more than a few minutes.
To give you an actual example:
An aquamarine (SG=2.70) and 18ct gold (SG=15.5) ring weighs 35.32 cts.
In water it weighs 28.75 carats
Loss of weight = 6.57 carats
If all aquamarine then weight would be 6.57 x 2.70 = 17.74
Extra weight due to gold = 35.52 – 17.74 = 17.58.
So loss of weight of mount is 17.58 divided by 15.5 – 2.7 = 1.37.
So loss of weight due to the stone is 6.57 – 1.37 = 5.20.
Weight of the stone is then 5.20 x 2.70 = 14.04 carats.
There are very minor differences in the SG of a gem species from stone to stone, and rather greater differences in the SG of gold of a given caratage (bullion dealers for this reason usually quote only to one place of decimals). But this method can usually be relied upon to give an answer well within 10% of the true weight of a stone. Where there are a few small diamonds included in the design one obviously needs to take these into account at the end of the main calculation by deducting say half a carat from the estimated weight of the main stone. Most jewelers are expert at estimating the weight of small diamonds by sight and should have little difficulty in making a reasonable correction for this situation. The method only really comes to grief when a mass of large stones of mixed species are found in one mount, and even then some guidance can be obtained from the exercise if it is used intelligently.
Taaffeite
Chemistry: Beryllium magnesium aluminate.
Crystal system: Hexagonal; trapezohedral.
Color: Transparent; red, pink, blue, mauve, green.
Hardness: 8
Cleavage: -
Specific gravity: 3.613
Refractive index: 1.718 – 1.723; Uniaxial negative; 0.004
Luster: Vitreous
Dispersion: -
Dichroism: -
Occurrence: Sri Lanka, China, Tanzania.
Notes
First discovered in 1945 by Count Taaffe; rare collector’s stone; appearance and values close to spinel but distinguished by birefringence; fluorescence: green in UV; faceted.
Crystal system: Hexagonal; trapezohedral.
Color: Transparent; red, pink, blue, mauve, green.
Hardness: 8
Cleavage: -
Specific gravity: 3.613
Refractive index: 1.718 – 1.723; Uniaxial negative; 0.004
Luster: Vitreous
Dispersion: -
Dichroism: -
Occurrence: Sri Lanka, China, Tanzania.
Notes
First discovered in 1945 by Count Taaffe; rare collector’s stone; appearance and values close to spinel but distinguished by birefringence; fluorescence: green in UV; faceted.
Saturday, August 11, 2007
The Emperor's New Clothes
Memorable quote (s) from the movie:
The Emperor (Sid Caesar): How do you spin a thread out of a solid diamond?
Henry Dispenser (Robert Morse): Ah! That is a family secret!
The Emperor (Sid Caesar): How do you spin a thread out of a solid diamond?
Henry Dispenser (Robert Morse): Ah! That is a family secret!
Can You Identify This Stone?
(via The Canadian Gemmologist, Vol.III, No.3, Spring, 1982) . I come in a variety of colors, almost any color in fact, though most people think of me as a green stone which is relatively inexpensive. I frequently show strong dichroism. In rough crystals, I am quite strongly striated parallel to the c-axis. They call me a hemimorphic crystal. What am I?
Answer: Tourmaline
Answer: Tourmaline
The Search: How Google And Its Rivals Rewrote The Rules Of Business And Transformed Our Culture
Good Books: (via Emergic) It's really amazing how search has become part of our life + today the concept is embedded in our modified lifestyle (for good or worse) + the book The Search: How Google and Its Rivals Rewrote the Rules of Business and Transformed Our Culture is a modified anthropological metamorphism of search + it also describes new ways of staying connected. A must-read book.
Amazon.com's review states:
This ambitious book comes with a strong pedigree. Author John Battelle was a founder of The Industry Standard and then one of the original editors of Wired, two magazines which helped shape our early perceptions of the wild world of the Internet. Battelle clearly drew from his experience and contacts in writing The Search. In addition to the sure-handed historical perspective and easy familiarity with such dot-com stalwarts as AltaVista, Lycos, and Excite, he speckles his narrative with conversational asides from a cast of fascinating characters, such Google's founders, Larry Page and Sergey Brin; Yahoo's, Jerry Yang and David Filo; key executives at Microsoft and different VC firms on the famed Sandhill road; and numerous other insiders, particularly at the company which currently sits atop the search world, Google.
The Search is not exactly the corporate history of Google. At the book's outset, Battelle specifically indicates his desire to understand what he calls the cultural anthropology of search, and to analyze search engines' current role as the "database of our intentions"--the repository of humanity's curiosity, exploration, and expressed desires. Interesting though that beginning is, though, Battelle's story really picks up speed when he starts dishing inside scoop on the darling business story of the decade, Google. To Battelle's credit, though, he doesn't stop just with historical retrospective: the final part of his book focuses on the potential future directions of Google and its products' development. In what Battelle himself acknowledges might just be a "digital fantasy train", he describes the possibility that Google will become the centralizing platform for our entire lives.
The most fascinating chapter in the book is the last one, where Battelle looks to the future.
Here is an excerpt which Battelle posted on his blog from the chapter entitled Perfect Search:
In the near future, search will metastasize from its origins on the PC-centric Web and be let loose on all manner of devices. This has already begun with mobile phones and PDAs; expect it to continue, virus-like, until search is built into every digital device touching our lives. The telephone, the automobile, the television, the stereo, the lowliest object with a chip and the ability to connect - all will incorporate network-aware search.
This is no fantasy; this is simple logic. As more and more of our lives become connected, digitized, and computed, we will need navigation and context interfaces to cope. What is TiVo, after all, but a search interface for television? ITunes? Search for music. That box of photographs under your bed and the pile of CDs teetering next to your stereo? Analog artifacts, awaiting their digital rebirth. How might you find that photo of you and your lover on the beach in Greece from fifteen years ago? Either you scan it in, or you lose it to the moldering embrace of analog obscurity. But your children will have no such problems; their photographs are already entirely digital and searchable - complete with metadata tagged right in (date, time, and soon, context).
The Search game has just begun. With it, we have seen a new business model emerge contextual advertising with pay-per-click. The recent announcement by Microsoft about making its applications available over the Web as services, in part paid for by advertising, takes the revolution started by Google even further. The combination of broadband and mobile networks is creating a new world. While Battelle's book may not answer questions about who will be tomorrow's winners (other than Google), it does a great job in laying out the story of Search and a company which today threatens incumbents across many industries by making the right information available at the right time.
Amazon.com's review states:
This ambitious book comes with a strong pedigree. Author John Battelle was a founder of The Industry Standard and then one of the original editors of Wired, two magazines which helped shape our early perceptions of the wild world of the Internet. Battelle clearly drew from his experience and contacts in writing The Search. In addition to the sure-handed historical perspective and easy familiarity with such dot-com stalwarts as AltaVista, Lycos, and Excite, he speckles his narrative with conversational asides from a cast of fascinating characters, such Google's founders, Larry Page and Sergey Brin; Yahoo's, Jerry Yang and David Filo; key executives at Microsoft and different VC firms on the famed Sandhill road; and numerous other insiders, particularly at the company which currently sits atop the search world, Google.
The Search is not exactly the corporate history of Google. At the book's outset, Battelle specifically indicates his desire to understand what he calls the cultural anthropology of search, and to analyze search engines' current role as the "database of our intentions"--the repository of humanity's curiosity, exploration, and expressed desires. Interesting though that beginning is, though, Battelle's story really picks up speed when he starts dishing inside scoop on the darling business story of the decade, Google. To Battelle's credit, though, he doesn't stop just with historical retrospective: the final part of his book focuses on the potential future directions of Google and its products' development. In what Battelle himself acknowledges might just be a "digital fantasy train", he describes the possibility that Google will become the centralizing platform for our entire lives.
The most fascinating chapter in the book is the last one, where Battelle looks to the future.
Here is an excerpt which Battelle posted on his blog from the chapter entitled Perfect Search:
In the near future, search will metastasize from its origins on the PC-centric Web and be let loose on all manner of devices. This has already begun with mobile phones and PDAs; expect it to continue, virus-like, until search is built into every digital device touching our lives. The telephone, the automobile, the television, the stereo, the lowliest object with a chip and the ability to connect - all will incorporate network-aware search.
This is no fantasy; this is simple logic. As more and more of our lives become connected, digitized, and computed, we will need navigation and context interfaces to cope. What is TiVo, after all, but a search interface for television? ITunes? Search for music. That box of photographs under your bed and the pile of CDs teetering next to your stereo? Analog artifacts, awaiting their digital rebirth. How might you find that photo of you and your lover on the beach in Greece from fifteen years ago? Either you scan it in, or you lose it to the moldering embrace of analog obscurity. But your children will have no such problems; their photographs are already entirely digital and searchable - complete with metadata tagged right in (date, time, and soon, context).
The Search game has just begun. With it, we have seen a new business model emerge contextual advertising with pay-per-click. The recent announcement by Microsoft about making its applications available over the Web as services, in part paid for by advertising, takes the revolution started by Google even further. The combination of broadband and mobile networks is creating a new world. While Battelle's book may not answer questions about who will be tomorrow's winners (other than Google), it does a great job in laying out the story of Search and a company which today threatens incumbents across many industries by making the right information available at the right time.
Spray The Ketchup, Fling The Lettuce
David Galloway writes about John Bock’s interdisciplinary fusion of language, fashion, film, video, performance, and installation + his specialty in 'suitcase performances' + his work (s) that has a character of its own + other viewpoints @ http://artnews.com/issues/article.asp?art_id=2038
The Travels Of A Lady-Wearing-Rough Into A Legal Kimberley Process Hole
Chaim Even-Zohar writes about creative ways of smuggling large rough diamonds + Kimberley Process Certification Scheme's (KPCS) oversight + a new look in the rough diamond jewelry + other viewpoints @ http://www.idexonline.com/portal_FullEditorial.asp
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