Fluorescent Fluorite. Important Notices

Transcription

1 The Crystal Gazette Vol 52 # 02 February 2013 STONE OF THE MONTH Fluorite Blue John Vase Fluorescent Fluorite Important Notices Annual General Meeting: 15th Feb 2013, AGM Club rooms, 19 4 th Ave, St Peters, 7pm Start Management Committee Meeting: 14th March, 6pm, Room 428, 38 Gawler Place Adelaide

2 TERACAST Diamond Merchants T F Suite 403, 38 Gawler Place Adelaide SA louise@teracast.com.au Contact Louise Important Contacts: President: Sue Arthur, FGAA,Dip DT,Cert IV T&A, M Secretary: Sandra Pimlott, FGAA, Dip DT Ph Treasurer: Don Bennett B.E. FGAA Ph Education: Tanya Cerny FGAA, Dip DT M Lise Jensen FGAA, Dip DT M

3 Page 3 Gem Fluorite Octahedral Fluorite Blue John Fluorite (also called fluorspar) is a halide mineral composed of calcium fluoride, CaF2. It is an isometric mineral with a cubic habit, though octahedral and more complex isometric forms are not uncommon. Crystal twinning is common and adds complexity to the observed crystal habits. Fluorite is a colorful mineral, both in visible and ultraviolet light, and the stone has ornamental and lapidary uses. Industrially, fluorite is used as a flux or smelting, and in the production of certain glasses and enamels. Optically clear transparent fluorite lenses have low dispersion, so lenses made from it exhibit less chromatic aberration, making them valuable in microscopes and telescopes. Fluorite optics are also usable in the far-ultraviolet range where conventional glasses are too absorbent for use. Occurrence and production Fluorite may occur as a vein deposit, especially with metallic minerals, where it often forms a part of the gangue (the surrounding "host-rock" in which valuable minerals occur) and may be associated with galena, sphalerite, barite, quartz, and calcite. It is a common mineral in deposits of hydrothermal origin and has been noted as a primary mineral in granites and other igneous rocks and as a common minor constituent of dolostone and limestone. Fluorite is a widely occurring mineral which is found in large deposits in many areas. Notable deposits occur in China, Germany, Austria, Switzerland, England, Norway, Mexico, and both the Province of Ontario and Newfoundland and Labrador in Canada. Large deposits also occur in Kenya in the Kerio Valley area within the Great Rift Valley. In the United States, deposits are found in Missouri, Oklahoma, Illinois, Kentucky, Colorado, New Mexico, Arizona, Ohio, New Hampshire, New York, Alaska, and Texas. Fluorite has been the state mineral of Illinois since At that time, Illinois was the largest producer of fluorite in the United States, but the last fluorite mine in Illinois was closed in Cubic crystals up to 20 cm across have been found at Dalnegorsk, Russia.The largest documented single crystal of fluorite was a cube 2.12 m in size and weighing ~16 tonnes. "Blue John" One of the most famous of the older-known localities of fluorite is Castleton in Derbyshire, England, where, under the name of Derbyshire Blue John, purple-blue fluorite was extracted from several mines or caves, including the famous Blue John Cavern. During the 19th century, this attractive fluorite was mined for its ornamental value. The mineral Blue John is now scarce, and only a few hundred kilograms are mined each year for ornamental and lapidaryuse. Mining still takes place in both the Blue John Cavern and the nearby Treak Cliff Cavern. Recently discovered deposits in China have produced fluorite with coloring and banding similar to the classic Blue John stone. Fluorescence Many samples of fluorite exhibit fluorescence under ultraviolet light, a property that takes its name from fluorite. In fluorite, the visible light emitted is most commonly blue, but red, purple, yellow, green and white also occur. Color Fluorite comes in a wide range of colors and has subsequently been dubbed "the most colorful mineral in the world". The most common colors are purple, blue, green, yellow, or colorless. Less common are pink, red, white, brown, black, and nearly every shade in between. Color zoning or banding is commonly present. The color of the fluorite is determined by factors including impurities, exposure to radiation, and the size of the color centers. 3

4 DETECTING HPHT SYNTHETIC DIAMOND USING A HANDHELD MAGNET Kirk Feral This study investigated the effectiveness of a handheld magnet in detecting synthetic diamonds. A total of 104 synthetic diamonds from nine different manufacturing sources were tested. Of the HPHT-grown synthetic samples tested, 58% registered a detectable magnetic response. Strong N52- grade neodymium magnets were able to detect 35% more HPHT synthetics than traditional ferrite and alnico magnets. CVD-grown synthetic diamonds showed no magnetic attraction. A set of 168 natural diamonds, including HPHTtreated natural diamonds, was tested as a control group. None of the natural transparent diamond samples showed attraction to a neodymium magnet, but two heavily included translucent specimens with unusually large opaque inclusions were strongly magnetic. A new magnetic testing method is presented for detecting small magnetic inclusions in loose HPHT-grown products, and for identifying small synthetic diamonds mounted in jewelry. feral.html Australian scientists explain photochromism phenomenon in pink diamonds A group of scientists at the University of Western Australia have managed to explain the photochromic behavior of pink diamonds, which refers to the stone's tendency to change of color when exposed to light. Writing in the journal, Diamond and Related Materials, the lead author Keal Byrne explained that natural pink diamonds have defect centers that allow optically controllable and reversible photochromism at room temperature. "We have pumped these diamonds with various wavelengths of light and measured the response in both time and absorption intensity," he wrote. "What we've seen is that the diamond color - the amount of absorption that gives it the pink color - is dependent on both the wavelength and intensity of the light, and what that is consistent with is a model of electron transfer between the unknown pink defect and other defects in the lattice." The paper explained that the pink coloration arises from "absorption bands centered at 550 nanometers and 390 nanometers." The diamond can be "bleached," or made lighter, under ultraviolet illumination, while the darker color can be restored with longer-wavelength light. The researcher wrote that the pumped-in light caused competing types of photoionization at different defect centers, producing photochromism. They found that while the defect centers are responsible for other diamond colors, among them blue and yellow, the defects themselves do not explain how pink diamonds get their specific hue. The color center responsible for the pink coloration, however, is still unknown. "So we're trying to work out what these new energy levels are that are unique to the pink diamond and by that way we can work out what properties it has and what use it might have," Byrne wrote. 4

5 Notes & Reminders TO REGISTER for any GAA course PLEASE CONTACT: Education: Tanya Cerny FGAA,. M or Lise Jensen FGAA M or Secretary Sandra Pimlott , sandrapimlott676@hotmail.com 2013 Courses Commencing dates Please note there has been a price increase in some courses. 1. Intro to Gemmology 13 th & 20 th Apr, Aug, Nov- $295 This basic course is designed for jewellers, hobbyists or for people traveling overseas. Gems and Gemmology provides students with an opportunity to assess whether they wish to proceed with a range of more advanced short courses or the intensive two year Diploma in Gemmology. 2. Diamond Grading 28 th May-31 st May 9am-5pm-$1750 M, $2250 NM Learn the intricacies of diamond grading and be able to explain differences in a diamonds colour, clarity or cut and be confident in your ability to point out the advantages or disadvantages of each. Maximise your diamond knowledge for profit and pleasure. In this course the emphasis is on practical work, so most of your time is spent with handling diamonds and the various instruments used to grade them. At the end of this course you will be able to grade any diamond to certificate standard on the international scale. 3. Advanced Diamond Grading or Synthetics Update TBA-$750 M $950 NM 4. Intro to Antique Jewellery- TBA-$ Gemmology Update- $2750* 6. Retail Diamond Consultancy- TBA- $ Pearl & Bead threading- TBA- $245 M $265 NM *Course offered depending on numbers enrolling Note :- Prices given are members prices- Non-members please contact Secretary for prices ROOMS ATTENDANCE AND VOLUNTEERS The GAA lab is open to the public between 10am-2pm. As members, you are welcome to come in and use the instruments in the lab for free. Membership Fees for 2013 are due. The price for 2013 is $185. Can you please forward this to our treasurer, Don Bennet. It would be greatly appreciated if they can be paid as soon as possible. LIBRARY BOOKS- Would any members who have books on loan from the Library please return them as soon as possible to the rooms. Thanks, The Librarian 5

6 SAVE THE DATE! HIGH TEA Sun 14 th April Time :2.30-5pm at Stamford Grand Adelaide Hotel. We are organising a social event for members of the GAA. Come along, meet other members and catch up with old friends. More details to follow! Spend A Minute With Your Council Members... William F Ashford William recently retired from the Federal Publicity Officer role. 2 years He as also held positions of SA DIV Vice President and SA DIV President between William is a Qualified Jeweller (Retired), Qualified Cert IV Gemmologist (Practising), Practical Diamond Grader (Practising) - Part Time Gem 2 Theory Lecturer, Volunteer Gemmologist(Analytical) on GAA (SADIV) Laboratory Open Days (Fridays 10am-2pm) AND a FULL-TIME Single Dad 1, What is it about gemmology that you love and what first attracted you to gemmology? I love the Scientific Research/ Analysis aspect of Gemmology, but even more so, I love TEACHING and passing on to Students what I ve learned myself... What attracted me to Gemmology? A serious Hard Rock Gold Mining accident left me with permanent disabilities. So I undertook Gemmological Studies (A gentler Science), I haven t looked back since, there Is ALWAYS something new! 2, What is your favourite gemstone or mineral? Why? A hard question to answer, I have to be completely honest and say I love ALL Gemstones (Each Has it s own peculiar Beauty)...Mineral/s would have to be GOLD or SILVER, Nothing better than Hand Forging a lump of metal into a Fine piece of Jewellery to set a great Gemstone into! 3, How long have you been a member of the GAA? Since , What is the best advice you have ever been given? Good, Better, Best... Never be at Rest...Until Your GOOD is BETTER...And Your BETTER... BEST!!! - Compliments of my Dear old Mum! 5, What is your favourite book/song?favourite Book Jonathan Livingston Seagull (Inspirational!) and Favourite Song The Happy Wanderer (SAS Regiment Theme Song Version) 6, Where was you favourite holiday, or where would you love to visit? My Favourite Holiday was taking my 6 Year old (at the time) Daughter to Singapore Zoo then on to Egypt (In peace-time in 2008). It was a lifelong dream come true, seeing the Pyramids, Karnak Temple-Thebes, sailing the Nile River in a felucca (sailing boat), Visiting the Cairo Museum but one day hope to visit the Ancestral Castle at Cape Wraith in the North West Highlands of Scotland. 7, What is your earliest memory? At the age of 2, helping my Late Father to fix the Family Car (an old FX Holden) in the back yard in Mount Isa Queensland where I was born, a significant memory because I remember the back yard was covered in crushed coal to keep the red Bull-Dust of the Outback down. 8, If you could invite 3 people over for dinner, who would they be? Galileo, Albert Einstein and my Brother Ian ( All 3 are gentle intellectuals). 6

7 Sixty Fifth Annual General Meeting Agenda for Friday the 15 th of February 2013, at the AGMC Rooms, 19 4 th Ave St Peters. 7pm Meeting Preliminaries including payment of subscriptions and finalising of nominations and proxies for AGM. 8.00pm Annual General Meeting- Business Agenda 1. Confirmation of minutes of the Sixty Third Annual General Meeting 2. To receive the Annual Report and Balance sheet for the period ending 31 st December Elect a President. 4. Elect a Vice President. 5. Elect an Honorary Secretary 6. Elect an Honorary Treasurer. 7. Elect an Honorary Minutes Secretary. 8. Elect an Honorary State Branch Editor. 9. Elect Honorary Education Officers. 10. Elect an Honorary Federal & Constitutional Officer & State Division Representative to the GAA. 11. Elect an Honorary Social Secretary 12. Elect an Honorary Librarian. 13. Elect an Honorary Program Officer 14. Elect an Honorary Membership Officer 15. Elect such number of councillors to bring the number of elected to Council to a maximum of Elect an Honorary South Australian Agent for Auditor. 17. Elect two delegates to the Federal Council and Conference 18. To transact any other business of which due notice has been given 19. Reminder: In order to vote or nominate at the AGM, members must be financial. Proxy and Nomination Forms are on Page 8. 7

8 Proxy Voting Form FOR THE AGM OF THE GEMMOLOGICAL ASSOCIATION OF AUSTRALIA SOUTH AUSTRALIAN DIVISION INC. I hereby appoint... to be my Proxy at the Annual General Meeting of the Gemmological Association of Australian Division on Friday 15 th February 2013 at 7.00pm Signed... [Please hand proxy votes to the Honorary Secretary at least one Hour before the start of the AGM] NOMINATION FORM FOR OFFICE BEARERS 2013 NAME POSITION PROPOSER SECONDER SIGNATURE OF NOMINEE Nomination forms are to be posted or handed to the President to reach her one hour before the start of the Annual General Meeting. Members wishing to stand for office must be financial Members of the Association. Subscriptions for 2013 is $185. Please ensure this is paid before voting. 8

9 To access the GAA Web Page, please visit On home page on right hand side go to Member tab and enter in user name which is your own address and password which is gaa2012. If you have trouble accessing, then we may not have your current address. Please provide to your State Division.Once you have access, go to Update your details. If you are an FGAA then you are eligible to tick the Directory Opt In box if you wish to be part of the Find a Gemmologist service. You can also log a job opportunity through the Employment section. You also need to change your password to secure your details. IMPORTANT. Then SAVE at the bottom of the page. The GAA e-learning suite Go to and follow the links 1. Introduction to Diamonds 2. Introduction to Coloured Gemstones 3. Introduction to Daily Jewellery Retail Business 4. Introduction to Jewellery 5. Introduction to Retail Jewellery Sales brought to you by the GAA 6. Introduction to Opals and Pearls - brought to you by the GAA Experts gathering in York to uncrack mystery of medieval sapphire ring A group of experts will be gathering in the ancient British walled city of York this January to try and crack the mystery of a sapphire ring that was found near the city in Archeologists have been unable to agree as to the origin of ancient items of jewelry, which includes the second earliest example of the use of sapphire ever found in the country. The sapphire ring was first discovered about 10 kilometers south of York by Michael Greenhorn, a hobbyist using a metal detector. He sold it to the museum for 35,000 pounds sterling. Intricately designed from gold, the ring is set with glass and a six-millimeter deep blue sapphire, and measures around 2.5 centimeters in diameter. Historians believe that it belonged to Anglo-Saxon or Viking royalty or aristocracy, or possibly to a senior member of the clergy. It is the only Anglo-Saxon era sapphire ever found in Britain, other than the St. Edward's sapphire, which Queen Elizabeth II wears in her Imperial State Crown at the opening of Parliament. That gem was once part of King Edward the Confessor's finger ring and is now the oldest gem in the British crown jewels. The Yorkshire Museum hopes that by launching a multi-disciplinary investigation, it will be able to discover the exact origin of the ring. It is believed that it most probably dates from the early 10th century to the mid 11th century, but some have said that it comes from as far back as the 7th century. The experts will attempt to narrow down the age range by looking for stylistic parallels in other pieces of Anglo-Saxon and first millennium jewelry. The gold alloy is quite sophisticated, containing 90 percent gold, 8 percent silver and 2 percent copper. The sapphire is believed to originate from India or Sri Lanka. An electron microscopy examination of the gem will be carried out to identify trace elements, which could give pointers as to its exact origin. In medieval times sapphires were believed to hold magical properties, capable of protecting kings and other ruling officials against death by poisoning. The sapphire's ability to act as an antidote to poison could be tested by swinging it above a spider. If the spider died, the sapphire was deemed to be powerful enough. 9

10 2013 GAA Calender Month General Meeting Other Events February AGM, Fri 15th Gem 1 and Gem 2 lessons begin March Fri 22nd Gemboree: 29 th March - 2 nd April April Fri 26th Intro to Gems May No General Meeting GAA Annual Conference in Melbourne, 25th- 28th Practical Diamond Grading, 27th-31st Skillex Careers Expo June No General Meeting Class of 2012 Graduation Dinner July Fri 26th August Fri 23rd Intro to Gems September Fri 27th October No General Meeting EOY Exams November No General Meeting Intro to Gems December No General Meeting Please note these dates may change. Watch this space for upcoming events and date changes. 10

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