Cutting Cubic Zirconia

(via Gem Cutter, March 1982) Wahroongai News writes:

We have been asked to furnish information about cutting cubic zirconia. As is usual in the faceting field, various cutters develop their own techniques but a little research brought the following results:

The recommended proportions appear to be 1/3 crown and 2/3 pavilion with the table 55% of the width. For cutting round brilliants, one cutter suggest crown mains 35º and pavilion 41º whilst another quotes 34½º and 40¾º respectively. The critical angle is specified as 28º. Yet another experienced cutter stated that the Barion cut, originally developed for diamond cutting, is quite ‘spectacular’ in cubic zirconia.

‘Make haste slowly’ is the opinion of some facetors; it is necessary to proceed by degrees. First use 600 micron diamond on a copper lap with water; followed by 1200 micron on copper with oil; then 3000 micron on copper with oil. Don’t overdo the diamond—a little goes a long way with cubic zirconia.

A smooth lap is needed—a well worn one seems to work best. And—avoid contamination at all costs! Another opinion was that one needed to use only a medium diamond disc (260 grit) and then proceed to polish. All agreed that a fine satin finish at this stage meant less polishing and that the polishing should be done with Linde A on a tin lap, well scored, and at a moderately slow speed. The only alternatives suggested were ¼ micron diamond dust on a zinc or a ceramic lap.

Incidentally, it is interesting to note that cubic zirconia was originally produced for scientific and technological purposes and its use in the gem and jewelry trade was merely a side issue. Also, the colors in which is now produced are derived by purposely adding, usually a minute quantities, some impurity (called ‘dopant’) and that many of these additives are rare-earths.

Dopant used: Cerium; Color produced: Yellow-orange-red
Dopant used: Chromium; Color produced: Olive
Dopant used: Cobalt; Color produced: Lilac
Dopant used: Copper; Color produced: Yellow
Dopant used: Erbium; Color produced: Pink
Dopant used: Europium; Color produced: Pink
Dopant used: Holmium; Color produced: Pink
Dopant used: Iron; Color produced: Yellow
Dopant used: Manganese; Color produced: Brown-violet
Dopant used: Neodymium; Color produced: Lilac
Dopant used: Nickel; Color produced: Yellow-brown
Dopant used: Praseodymium; Color produced: Amber
Dopant used: Thulium; Color produced: Green
Dopant used: Titanium; Color produced: Yellow-brown
Dopant used: Vanadium; Color produced: Green

Old Chinese Snuff Bottles

By Henry C Hitt
Charles E Tuttle Company
1978 ISBN 0-8048-1220-9

Charles E Tuttle Company writes:

Among collectors of Chinese snuff bottles, the name of the late Henry C Hitt has long commanded respect, not only as that of an ardent fellow collector but also as that of the author of the first book on the subject in any language—a work that had the great value of arousing collectors everywhere, even in China. This book, which appeared in first and second editions and was followed by a supplement, has in itself become a collector’s item. Until now, however, it has been practically impossible to obtain, for it was a handmade book produced by lithographic methods, and it had little hope of ever being reprinted. The present edition remedies this lack by bringing together facsimile copies of the expanded second edition (1945) and the supplement and thereby making available to a much wider audience Mr Hitt’s invaluable contribution to the fascinating subject of snuff bottle collecting.

In this introduction to the second edition, Mr Hitt wrote: “There is an almost total lack of literature on Chinese snuff bottles. This is, as far as is known, the only book on the subject, and there have been only a few magazine articles.” To be sure, since the appearance of the book in 1945 there have been numerous other books and articles on the subject, but this by no means diminishes the value of his pioneering work or the honor he achieved by being one of the first to share his knowledge with other enthusiastic collectors. And it is exactly for the benefit of these enthusiastic collectors that this new facsimile edition is being offered.

Weakly Radioactive Spinel Triplets

(via ICA Early Warning Flash, No.23, November 1989) Kurt Nassau writes:

A New York gemstone merchant accidentally placed a parcel of spinel triplets near his Geiger counter and was surprised when radioactivity was detected. Some of the stones involved were examined by me. They are yellow green, apparently intended to imitate peridot, and are said to be manufactured in Europe. Analysis shows that they consist of two layers of colorless spinel cemented together with a green lead and uranium-containing glass. The uranium provides both the color and the radioactivity. A single stone counts only just double the background on a small ‘monitor 4’ Geiger counter; accordingly the amount of radiation produced from an individual stone is not easy to detect and probably harmless. Nevertheless, significant activity is given off by a parcel containing many such stones. Gemologists and dealers should be aware of this situation.

Sideways

Memorable quote (s) from the movie:

Maya (Virginia Madsen): You know, can I ask you a personal question, Miles?

Miles Raymond (Paul Giamatti): Sure.

Maya (Virginia Madsen: Why are you so in to Pinot? I mean, it's like a thing with you.

Miles Raymond (Paul Giamatti): Uh, I don't know, I don't know. Um, it's a hard grape to grow, as you know. Right? It's uh, it's thin-skinned, temperamental, ripens early. It's, you know, it's not a survivor like Cabernet, which can just grow anywhere and uh, thrive even when it's neglected. No, Pinot needs constant care and attention. You know? And in fact it can only grow in these really specific, little, tucked away corners of the world. And, and only the most patient and nurturing of growers can do it, really. Only somebody who really takes the time to understand Pinot's potential can then coax it into its fullest expression. Then, I mean, oh its flavors, they're just the most haunting and brilliant and thrilling and subtle and... ancient on the planet.

Absorption Spectrums

(via Wahroongai News, Volume 32, Number 7, July 1998)

Table of absorption lines for gems and minerals: This section deals with the absorption spectra of gemstones by using the spectroscope. The units are measured in Angstrom units (A), (One Angstrom = one ten millioneth of a millimeter), all figures are in Angstrom units. The gem spectroscope is used on transparent materials but thin slices of opaque materials can be used as long as light passes through it. Strong absorption lines are bracketed and weak lines have no brackets.

Color bands for the spectroscope
Red: 7800 – 6400
Orange: 6400 – 5950
Yellow: 5950 – 5700
Green: 5700 – 5000
Blue: 5000 – 4500
Purple: 4500 – 3800

Agate, dyed yellow: (7000), 6650, 6350
Actinolite: 5030, 4315
Alexandrite, green direction: (6805), 6785, 6650, (6550), 6490, 6450, (6400), (5550)
Alexandrite, red direction: 6805, (6785), 6550, 6450, 6050, 5400, (4720)
Almandine: 6170, (5760), (5270), (5050), 4620, 4380, 4280, 4040, 3930
Amethyst: 5500, 5200
Andalusite: 5535, (5505), 5475, 5250, 5180, 5060, 4950, (4550), 4475, (4360)
Apatite, yellow green: 6053, 6025, 5975, (5855), (5772), 5335, 5295, 5270
Aventurine: 6820, 6490
Axinite: 5320, (5120), (4920), (4660), 4400, 4150
Azurite: 5000
Beryl, dyed blue: 7050, 6850, 6450, 6250, 6050, 5870
Calcite: (5820)
Chalcedony, dyed blue: 6900, 6600, 6270
Chalcedony, dyed green: 7050, 6700, 6450
Chrysoberyl: 5040, 4950, 4850, (4450)
Chrysoprase, dyed: 6320, 4439
Chrysoprase: 4439
Danburite: 5900, 5860, (5845), 5840, 5830, 5820, 5805, 5780, 5760, 5730, 5710
Demantoid: (7100), 6930, (6400), (6220), 4850, 4640, 4430
Diamond, colorless to yellow: (4780), 4650, 4510, 4350, 4230, (4155), 4015, 3900
Diamond, brown to green: 537-, (5040), 4980
Diamond, yellow to brown: 5760, 5690, 5640, 5580, 5500, 5480, 5230, 4935, 4800, 4600
Diamond, artificial color yellow: (5940), 5040, (4980), 4780, 4650, 4510, 4350, 4230, 4155
Diamond, artificial color green: (7410), (5040), (4980), 4650, 4510, 4350, 4230, 4155
Diamond, artificial color brown: (7410), 5940, (5040), (4980), 4780, 4650, 4510, 4350, 4230, 4155
Diopside: (5470), 5080, (5050), (4930), 4560
Chrome diopside: 6700, 6550, 6350, 5080, 5050, 4900
Dioptase: 5700, 5600, 4650-4000
Ekanite: 6651, 6375
Emerald: (6835), (6806), 6620, 6460, (6370), 6060, 5940, (6300-5800)
Emerald, synthetic: 6830, 6805, 6620, 6460, (6375), 6300-5800, 6060, 5940, 4774
Enstatite: (5475), 5090, (5058), 5025, 4830, 4720, 4590, 4490, 4250
Chrome Enstatite: 6880, 6690, 5060
Epidote: 4750, (4550), 4350
Euclase: (7065), (7040), 6950, 6880, 6600, (6500), (6390), 4680, 4550
Fluorite, green: 6400, 6006, (5850), 5700, 5530, 5500, 4520, 4350
Fluorite, yellow: 5450, 5150, 4900, 4700, 4520
Gahnite: (6320), 5920, 5770, 5520, 5080, (4800), (4590), 4430, 4330
Grossular: 6300
Hematite: 7000, 6400, 5950, 5700, 4800, 4500, 4250, 4000
Hessonite: 5470, 4900, 4545, (4350)
Hiddenite: (6905), (6860), 6690, 6460, (6200), (4375), 4330
Hypersthene: 5510, (5475), (5058), 4820, 4485
Idocrase, green: 5300, 4870, (4610)
Iolite: 6450, 5930, 5850, 5350, (4920), (4560), 4360, 4260
Jadeite, green: (6915), 6550, 6300, 4950, 4500, (4375), 4330
Jadeite, artificial green: 6650, 6550, 6450
Kornerupine: 5400, (5080), 4630, (4460), 4300
Kyanite: 7060, 6890, 6710, (4460), 4330
Nephrite: 6890, (5090), 4900, 4600
Obsidian: 6800, 6700, 6600, 6500, 6350, 5950, 5550, 5000
Opal, fire: 7000-6400, 5900-4000
Orthoclase: 4480, 4200
Peridot: 6530, 5530, 5290, (4970), (4950), (4930), (4730), 4530
Petalite: 4540
Pyrope: (6870), (6850), 6710, 6500, (6200-5200), 5050
Quartz, synthetic blue: 6450. 5850, 5400, 5000-4900
Rhodochrosite: 5510, 4545, 4100, 3910, 3830, 3780, 3630
Rhodonite: 5480, 5030, 4550, 4120, 4080
Ruby: (6942), (6928), 6680, 6592, 6100-5000, (4750), (4685)
Sapphire, blue: (4710), (4600), 4550, (4500), 3790
Sapphire, yellow: (4710), (4600), (4500)
Sapphire, green: 4710, 4600-4500
Scheelite: (5840)
Serpentine: 4970, 4640
Sillimanite: 4620, 4410, 4100
Sinhalite: 5260, 4925, 4760, (4630), 4520, 4355
Scapolite, pink: 6630, 6520
Spessartite: 4950, (4845), 4810, 4750, (4620), 4570, 4550, 4400, 4350, 4320, 4240, 4120, 4060, 3940
Sphalerite: 6900, 6650, (6510)
Sphene: 5900, (5860), (5820), 5800, 5750, 5340, 5300, 5280
Spinel, red: (6855), 6840, (6750), (6650), 6560, 6500, 6420, 6320, (5950-4900), 4550
Spinel, blue: (6350), (5850), (5550), 5080, (4780), (4580), 4430, 4330
Spinel, synthetic blue: 6340, 5800, 5440, 4850, 4490
Spinel, synthetic green: 6200, 5800, 5700, 5500, 5400
Taaffeite: 5580, 5530, 4780
Tanzanite: 7100, 6910, (5950), 5280, 4550
Topaz, pink: (6828)
Tremolite: (6840), 6500, 6280
Turquoise: 4600, 4320, 4220
Tourmaline, red: 5550, 5370, 5250-4610, (4560), (4510), 4280
Tourmaline, green: (4970), (4610), 4150
Variscite: 6880, 6500
Willemite: 5830, 5400, 4900, 4425, 4315, (4210)
Zircon, normal: 6910, 6890, 6625, 6605, (6535), 6210, 6150, 5895, 5620, 5375, 5160, 4840, 4600, 4320
Zircon, low: (6530), 5200

What Is An Antique

(via Wahroongai News, Volume 32, Number 5, May 1998)

The following definition of an antique was discovered in the first newsletter of 1998 from the Queensland Antique Collector’s Society Inc.

Definition of Antiques
One of the strengths of the Society is the very wide range of subjects that can be covered under the definition of antiques, e.g. porcelain, silver, furniture, art. What is clear is that definition (of what is an antique) has suffered changes.

Until quite recently, the accepted opinion in England was that antique applied to articles made before about 1830, i.e. not including Victorian items. In view of the factors of supply and demand, English dealers have accepted the international convention that antique means more than 100 years old. This includes basically all Victorian pieces, but excludes Edwardian and most Art Nouveau.

American dealers have taken the view that antique refers to pieces made more than 30 years ago, and so would include original material of the Beatles and Elvis Presley. While this concept may appear startling to traditional conventions, the definition can change depending on personal perspective.

In other cultures, goods may be described as a little bit old referring to wares that were in use by grandparents. There are collectors who seek items because their grandma had one of those. The differing age of collectors, from 20 to 70 plus means that the time-frame for defining the previous two generations becomes flexible.

Most antique dealers take pragmatic view that antique refers to articles no longer made, for which there is demand. If pushed, they may limit the scope of the definition to items made before the Second World War, thus including Art Deco.

Bewitching Jewelry

By Carl H Giles & Barbara Ann Williams
A.S.Barnes and Co, Inc
1976 ISBN 0-498-01654-4

A S Barnes and Co writes:

Bewitching Jewelry opens the occult showcase of amulets and talismans. It examines the glittering and mystic trappings of the supernatural. Lean what the well-dressed witches are wearing—and why! Rip away the ritual robe and peek at the pendants, bracelets, rings, and necklaces of witchcraft.

Amulets and talismans are among the most powerful of all psychic baubles. Mysticism is universal, and amulets are common to all people. Talismans act more as lures to make things happen; amulets are usually used as shields, to safeguard the wearer from misfortunes.

Psychics claim that an amulet possesses supernatural powers, while a talisman may be a piece of jewelry or any object that has been endowed with special powers through occult ceremonies. Almost any object may become a talisman. Choosing the right amulet and talismans for your black arts jewelry box may help you become happier, healthier, and wealthier.

This witch’s jewel case exhibits the ornamental wonders that may help you achieve goals and fulfill ambitions. Learn how to recognize the pieces of bewitching jewelry that many men and women are wearing. You will know what people are trying to accomplish just by observing their occult jewelry.

Is your closest friend trying to revitalize her mate by wearing that special medallion? Should you wear a certain item to stop gossip? Will the piece of jewelry and the right ritual words really get rid of a headache? Is it possible for some occult jewelry to increase your confidence? Amulets and talismans may do all these things.

Some occult stones and metals may be used for solving romantic problems. Regardless of what one wants to obtain or accomplish, there seems to be some jewelry appropriate to the situation. Would you wear a voodoo doll for love or hate? You can take one for whatever scheme you need after reading the chapter on how to choose talismans.

Should you wear a witch’s belt? You may make one with the directions outlines in this volume. Find out how you can fashion some special creations. Inventory your wishes and wants, and select psychic designs that will complement your wardrobe.

Bewitching Jewelry may improve your life by giving you a detailed look at all the occult ornaments needed for an occult jewelry box. The supernatural charms and jewelry will radiate a great, new betwitching you on the outside and may generate a beautiful new mental you on the inside. Start doing your betwitching best.

If We Learn To Appreciate What Mines Produce, There Will Be Enough Rough

(via ICA Gazette, April 1990) E Julius Petsch writes:

“We have no rough stones available.”
“There is no more rough.”
“This is the last lot from this mine.”

How many times have I heard these arguments? And in almost every case the people using them were wrong.

There have always been rough gemstones available. I can look back on thirty years of experience in the rough colored gemstone business and during each buying trip those years I found that were more rough stones available than money to pay for them.

During these years I have also collected a great deal of experience in mining and it is very rare to hear about a mine that is actually depleted. What most often disturbs the steady flow of rough is the lack of long term planning and lack of capital to finance proper mining. In fact, even today, only a very few mines are being exploited with the expertise and knowledge of experienced mining engineers and geologists. Many mining enterprises are also handicapped by lengthy quarrels about mining rights or legal possession of the claims. Mines are invaded by prospectors who only dig holes in the ground instead of carrying out a proper mining plan. There are also unrealistic or exaggerated price demands from inexperienced mine owners or prospectors which discourage buyers from trying to create a market for a product.

It also must not be forgotten that in some gemstone producing countries the existence of very rigid laws concerning the export of rough constrains the market. In other producing countries, the uncertain political situation impedes the production of rough gemstones or the government interferes with free trade and mining, often imposing unsupportable conditions on those who would be willing to work in this industry.

Most of the mines and mining areas which are producing today are not recent discoveries. Many mines have been producing for decades without interruption, some even for a century. The number of genuinely new discoveries of gemstone deposits is very small.

If research and prospecting for gemstone deposits were carried out more systematically, we would find that there are still vast reserves available. Most of the mining areas I know are rich with gemstone deposits. The Carnaiba emerald mine in Brazil, for example, has been proven to extend for 12 kilometers. The tourmaline bearing pegmatite of the Cruzeiro area, also in Brazil, in the State of Minas Gerais, measures many square kilometers in area. This deposit has been exploited steadily for more than fifty years. I could give very many more examples of the richness of existing deposits, not only in Brazil, but also in Australia, Africa, and the United States.

No gemstone mine produces only the best and finest qualities. The majority of the production is always the lower qualities. But this does not mean that this material is not beautiful or useful to the jewelry industry: this is a matter of taste and fashion. Cabochons, beads and tumbled stones are very often cut from the lower qualities. Although they are not clean and show inclusions instead of being transparent, they are often of beautiful color and show interesting layers, veins, and patterns. These stones are not as valued primarily because they are found in large quantities. Very often, jewelry set with a cabochon cut stone can be as fashionable, attractive, and impressive as jewelry set with its faceted counterpart.

If we could adjust the demand from the designers and manufacturers of jewelry to fit the availability of the various qualities of rough gemstones, we would always have sufficient material at our disposal to cover the demand for cut gemstones. Demand determines the price for each quality.

If however, we insist on only selling clean gemstones with intense pure colors, the availability of suitable rough is artificially decreased. I am convinced that the concentration of demand in narrow range of material has been created unnecessarily. The consumer always appreciates the natural beauty of a gemstone, be it transparent or translucent, faceted or cabochon cut, bead or tumbled. It is the gemstone itself with its natural beauty that the buyer loves, even more when that beauty is complemented by a fine gold or silver setting.

I am sure that colored gemstone rough—and therefore cut colored gemstones—will always be available, provided we can finally accept the wide range of qualities naturally produced by the world’s gemstone mines.