Aventurine glass is produced in Murano (near Venice) and the introduction of excessive metal oxide helps to form crystals large enough to reflect light. The copper in the glass shimmers.
Like many of these dials, it is difficult to capture well in a photograph and the depth of colour and degree of shimmer alter depending on the amount and angle of light hitting the dial.
It is a smooth material (well it is glass ) and this rarely shows well in photos. The actual colour is a deep blue which turns lighter as the light reflects.
You really have to see this dial to appreciate the beauty!
Best,
MaxH
This message has been edited by mkt32 on Apr 29, 2006 7:38 PM This message has been edited by mkt32 on Apr 28, 2006 4:57 PM
Spessartine is a pretty cool mineral and looks great on the new Ladies' J*D dials! It is actually composed of four elements; Manganese, Aluminium (that's Aluminum to our American readers ) Silicon and Oxygen, and has the chemical formula Mn2+3Al2(SiO4)3 (I know you were curious!)
It is named after its primary location, the Spessart Mountains in Bavaria, Germany. Clearly an area now famous for cars, beer and minerals!
It occurs naturally in colors ranging from reddish orange, yellowish brown, reddish brown and brown. It can range from transparent to translucent. It is crystalline, which means it forms fine sized crystals, and massive, in that they easily join together. It is also sub-conchoidal, which means it is brittle and fractures easily. It has a hardness of up to 7.5 (Diamond defines the scale at 10).
Cool image below (stolen from Webmineral.com)
Regards,
NickO
This message has been edited by mkt32 on Apr 29, 2006 7:38 PM
Curious, the dial appears metallic yet only about 6% of all meteorites are of the iron type.
It is an iron meteorite with a structural classification of Octahedrite (intermediate nickel with plates of kamacite and taenite interwoven to form a Widmanstatten pattern on etched faces) The octahedrite group is further divided by crystal size into subgroups: finest (Off), fine (Of), medium (Om), coarse (Og), and coarsest (Ogg). The above picture is an example of Om.
Best, Mike
This message has been edited by mkt32 on Apr 30, 2006 4:15 AM
Maybe not as sexy as some of the other, more spectacular looking dial materials but nonetheless.. not to be overlooked! Brings out the best in the rest
Regards
Mark
This message has been edited by mkt32 on Apr 29, 2006 2:40 PM
Mark had a query recently asking what opaline slate is.
The answer from the ever helpful J*D team is:
"Opaline is a surface quality achieved by sandblasting. This treatment produces a surface finish that appears to be completely matt yet slightly rough, but very pure.
The black or slate colouring that is typical of the Jaquet Droz brand is obtained by subsequent treatment in baths."
Don't you just love the thought of subjecting your precious J*D to bath treatment!
Spectrolite, the most valued type of labradorite, comes from Finland. The name is derived from Labrador which is the main and original source of the Canadian variety of this feldspar stone. Labradorite is also found in India, Madagascar, Newfoundland, and Russia
A type of translucent feldspar which displays strong iridescence when viewed from different angles, Finnish spectrolite exhibits vivid colors of bright aqua, golden yellow, peacock blue, reddish orange, greens and red.
Nuummite
Nuummite is a gemstone formed from a mixture of two minerals from the orthoamphibole group: anthophyllite and gedrite. The name nuummite is derived from the Municipality of Nuuk, where the stone was discovered in 1982. It has since been found in several localities in the outer part of the Godthabsfjord near Nuuk.
Geologically speaking, nuummite is of volcanic origin and was formed about 3 billion years ago. Subsequent influences on the rock (metamorphism) have given rise to the striking mixture of crystals which gives nuummite its unique appearance. Rocks resembling nuummite are also found in a few minor occurrences in the USA, but it is only in the Greenland type that coloration is developed well enough for the stone to be suitable for gemstones.
In nuummite, the two orthoamphibole, anthophyllite (Mg,Fe)7Si8O22(OH)2 and gedrite (Mg,Fe)5Al2(Al,Si)8O22(OH)2, both with a hardness of 5 to 5.6, constitute a mixture of elongated crystals, often in sheaf-like groups. In the transition between the individual crystals (and especially the thin ones), an optical effect is created causing a special “inner” golden brown glow. This effect is also called iridescence, and is especially distinct on polished surfaces. The result is that the crystals appear as bright lamellae, almost like flames in a fire. The colors vary somewhat between reddish, greenish, and bluish hues, sometimes even within the same lamella. Between the bright lamellae, the color is dark brown to black.
Nuummite is generally easy to polish, even though, in certain qualities of stones with many parallel crystals, it can be difficult to avoid holes and cracks. The usual shape is cabochon, but other convex finishes also produce pleasing results. In larger pieces it is possible to retain most of the colors of the iridescence, so that one end of the cabochon has a golden hue while the opposite end has a bluish tone. Nuummite is well suited to mounting in both gold and silver.
Best, Mike
This message has been edited by mkt32 on Oct 11, 2006 5:55 AM
Quartz is the most common mineral found on the surface of the earth. A significant component of many igneous, metamorphic and sedimentary rocks, this natural form of silicon dioxide is found in an impressive range of varieties and colours.
Inclusions of other minerals in rock crystal and smoky quartz are not particularly uncommon and are often highly attractive. To form rutilated quartz, earlier formed Rutile crystals were captured by later formed quartz as it grew thereby encasing the Rutile.
In some specific instances, such as asteriated quartz, rutile is thought to have been in solid solution in the quartz and, upon cooling, the rutile was forced out of the quartz structure, resulting in microscopic highly oriented needles. The light, playing off these oriented needles, presents a six-ray star typical of asterism ( a quartz version of star sapphire)
As you know, Grand Feu is a centuries-old technique of enamelling that enables one to achieve an enamel that is both extremely pure and particularly resistant. The perilous firing operations at extremely high temperatures make it possible to show incredibly precise details. However, as M. Emch has pointed out on many occassions, it also comes with extremely high reject rates
The great French enamalist (of British origin), Taxile Doat (1851-1939) is considered as the master of grand feu ceramics. His book "Grand Feu Ceramics: A practical treatise on the making of fine porcelain and grès" (1905) is probably a seminal read on the subject
Regarding the detailed technical process, here's what I found: Grand feu refers to high fire faience. High temperature kilns were used to fire the body and the glaze of porcelain or faience, between 1100 to 1450 degrees. The traditional polychrome decor which was brilliantly developed in Renaissance Italy consists of applying colors to an unfired tin glaze base or faience. Subsequent firing of the piece at 1000 degrees centigrade restrains the decor to the few colors that can take such a high temperature: blue, violet, green, yellow, orange. The unfired faience glaze constitutes a pulverulent layer that absorbs the pigment, allowing no mistakes or chance for correction by the painter. Upon firing the pigments blend with the base.
The best examples in horology that I can find are presented by J*D and Jaeger Le Coultre.
Stone's names: Onyx, Sardonyx (with white and brown bands).
Color: The layers in these stones range from translucent to opaque for sardonyx. The stones vary in color, too. They may be white or gray, ranging to many colorful varieties. Sardonyx stones usually contain flat-banded, white and brownish-red bands. Onyx is a gemstone with alternating light and dark bands, which are colored in brown, red, black, white and grey.
Description: SiO2 Onyx is striped, semiprecious variety of the silica mineral agate with white and black, brown or red alternating bands. Its properties are the same as those of quartz.
Birthstone: Sardonyx is the birthstone of Leo (Lion): July 23 - Aug 22.
Wedding anniversary: Onyx is the anniversary gemstone for the 7th year of marriage.
Black Onyx is the anniversary gemstone for the 10th year of marriage.
The name's origin: The word Sardonyx is derived from the Greek, Sard meaning "reddish brown," and onyx meaning "veined gem."
Varieties: Varieties of onyx include carnelian onyx, with white and red bands, and sardonyx, with white and brown bands.
Care and treatment: Onyx may chip or scratch rather easily, so store onyx carefully and never allow two specimens to touch each other.
From the stone history: The name onyx was used by the Romans for a variety of stones including alabaster, chalcedony, and what is now known as onyx marble. Roman soldiers wore sardonyx talismans engraved with heroes such as Hercules or Mars, god of war. They believed that the stone would make the wearer as brave and daring as the figured carved on it. During the Renaissance, sardonyx was believed to bring eloquence upon the wearer and was regarded with great value by public speakers and orators.
Cameos are cut from stones, such as onyx, sardonix or agate, where different colors occur in layers. The background material is cut away, leaving the cameo design in relief. Onyx is also used in intaglios because its layers can be cut to show a color contrast between the design and the background.
Sardonyx at one time was more precious than gold, silver, or sapphire. Sardonyx is always widely used in cameos and intaglios.
The main component of lapis lazuli is lazurite (25 to 40 percent), a feldspathoid silicate mineral composed of sodium, aluminium, silicon, oxygen, sulfur, and chlorine. Most lapis also contains calcite (white), sodalite (blue) and pyrite (yellow). Other possible constituents are augite, diopside, enstatite, mica, hauynite, hornblende and nosean. Lazurite's formula is (Na,Ca)8(AlSiO4)6(S,SO4,Cl)1-2.
Lapis lazuli usually occurs in crystalline limestones as a result of contact metamorphism.
Inclusions are common in lapis and are an important help in identifying the stone. The finest color is intense blue, lightly dusted with small flecks of golden pyrite. There should be no white calcite veins and the pyrite inclusions should be small. Stones that contain too much calcite or pyrite are not as valuable. Patches of pyrite are an important help in identifying the stone as genuine and do not detract from its value. Often, inferior lapis is dyed to improve its color, but these are often a very dark blue with a noticeable grey cast.
The finest lapis comes from the Badakshan area of Afghanistan. This source of lapis may be the oldest continually worked set of mines in the world, the same mines operating today having supplied the lapis of the pharaohs. More recently, during the 1980s conflict with the USSR, Afghani resistance fighters disassembled unexploded Soviet landmines and ordnance and used the scavenged explosive to help mine lapis to further fund their resistance efforts.
In addition to the Afghan deposits, lapis has been found in the Andes near Ovalle, Chile, where it is usually pale rather than deep blue. Other less important sources are the Lake Baikal region of Russia, Siberia, Angola, Burma, Pakistan, USA (California and Colorado) and Canada.
Obsidian is a type of naturally occurring glass, produced from volcanoes (igneous rock) when a fluid felsic lava cools rapidly and freezes without sufficient time for crystal growth, for example by flowing into a body of water. It consists mainly of SiO2 (silicon dioxide), 70% or more. Obsidian is mineral-like, but not a true mineral because it is not crystalline. Its composition is very similar to that of granite and rhyolite. It is sometimes classified as a mineraloid.
The color of obsidian varies depending on the presence of impurities. Iron and magnesium typically give the obsidian a dark green to brown to black color. The inclusion of small, white, radially clustered crystals of cristobalite in the black glass produce a blotchy or snowflake pattern (snowflake obsidian). It may contain patterns of gas bubbles remaining from the lava flow, aligned along layers created as the molten rock was flowing before being cooled. These bubbles can produce interesting effects such as a golden (sheen obsidian) or rainbow sheen (rainbow obsidian). Small nuggets of obsidian that have been naturally rounded and smoothed by wind and water are called "Apache tears." Obsidian is relatively soft with a typical hardness of 5 to 5.5. Its specific gravity is approximately 2.6.
Serpentine is a group of common rock-forming hydrous magnesium iron phyllosilicate ((Mg, Fe)3Si2O5(OH)4) minerals; it is also often rich in other metal ores, including chromium, manganese, cobalt and nickel.
Most serpentines are opaque to translucent, light (specific gravity between 2.2–2.9), soft (hardness 2.5–4), infusible and susceptible to acids. All are microcrystalline and massive in habit, never being found as single crystals. Lustre may be vitreous, greasy or silky. Colours range from white to grey, yellow to green, and brown to black, and are often splotchy or veined. Many are intergrown with other minerals, such as calcite and dolomite. Occurrence is worldwide; New Caledonia, Canada (Quebec), USA (northern California), Afghanistan, Cornwall, China, France, Norway and Italy are notable localities
Serpentine can be an attractive green stone that takes a nice polish and is suitable for carving. It has been used as a substitute for jade and is sometimes difficult to distinguish from jade, a testament to the beauty of finer serpentine material. Serpentine rocks are classified as common serpentine and precious serpentine, the common serpentine being darker, less translucent, and sometimes impure.
Paillons are the gold decoration pieces which are embedded in enamel and make the Paillonnee dial. The white, green and red decorations on the dial are also enamel.
Anita Porchet makes each dial from her rapidly diminishing stock of 18th century paillons - she uses about 175 on each dial - once they are gone...they are gone...there are no more!
On a visit to her workshop - a treasure trove, full of items of fascinating historical interest that are still in everyday use - Anita showed us her reference book of over 2000 paillons.
This technique is revived here for the first time, the enamel work with translucent effect.
The watch will be made in 3 different series, with each series a limited edition of 8 pieces only:
Dials base is solid white gold:
1) The dial is hand engraved with a sunray pattern
2) Application 2 to 3 layers of translucent blue enamel and one layer of counter-enamel on the
back of the dial. Each layer has to be baked in a oven at 820 degrees.
(Yummy! and the final version could be even better!)
3) Application of all the "paillons" (original engraved gold leaves from the 18th century)
4) Application of a layer of color enamel (red, white or yellow color over the "paillons"). The dial
goes into the oven once more.
(Gold leaves for good fortune?)
5) Application of 4 to 6 additional layers of translucent enamel layers, one after the other in the
oven.
Dumortierite is named for the French paleontologist, Eugene Dumortier who discovered it in 1881. It is a boro-silicate mineral. Notable Occurrences include the type locality of Beaunan, France as well as Quartzite, La Paz County, Arizona; Colorado; Oreana, Nevada; New York, New York and Alpine, San Diego County and Los Angeles County, California, USA; Magadanskaya, Siberia, Russia and Sahatany, Madagascar.
Color is typically blue to violet, but also pink and brown and has a hardness of 7 to 8.5 (Mohs'). Interestingly, it has been used in the past as an imitation lapiz lazuli in carvings. It is the most common boro-silicate with the exception of the Tourmaline group. It is used in the manufacture of high grade porcelain.
If you're interested in the metaphysical properties of this stone, dumortierite highly reduces difficulties of scattered mind and disorganization. In addition, it encourages one to see and accept reality, and react to it in an intelligent manner in one's own behalf. (this sounds like a good dial material for me)
Robert
This message has been edited by mkt32 on May 11, 2006 3:20 PM
Named for a Japanese geologist, Ken-ichi Sugi. who discovered it in 1944. It has a very distinctive opaque purple color and has been described as a 'purple turquoise' due to it's look, although there is no relation between the two minerals. Gem quality sugilite can be quite rare and thus can fetch a high price.
Generally found in Iwagi Island, Shikoku, Japan as well as Mont Saint-Hilaire, Quebec, Canada, the most important occurrence was found in 1975 in the Kalahari Desert, Northern South Africa. In 1979 a large deposit of gem grade sugilite was found 3200 feet below the original discovery.
It is said that sugilite strengthens the heart, aids physical healing and reduces stress. It is a balancer of mind, body and spirit and encourages peace of mind, a general feeling of well being and spiritual love. Sugilite also protects against and dissipates anger and other negative energies. (this also sounds like a good dial material for me!)
Pietersite- Originally posted by Adrian with pic from Jon Vargas
November 1 2006, 8:00 AM
Pietersite was discovered by Sid Pieters in 1962 while he was prospecting some farm land in Namibia, Africa. After his discovery, he registered the find in the mineral records of Britain. His discovery was published in 1964,and the material was named Pietersite. Currently there are only two known sources of Pietersite; China and Africa. These two forms of Pietersite,are similar, but still somewhat different from each other. The Chinese Pietersites' fibrous mineral is a magnesium-rich alkalic amphibole. The African (Namibian) variety is mainly crocidolite.
The China form of Pietersite was discovered in 1993, but did not come to market until 1997. This China Pietersite exhibits slightly different color variations from Mr. Pieter's original mineral, but both are beautiful and are now universally recognized as Pietersite.
The material found in China was formed from a very similar but different [not Crocidolite], mineral named Torendrikite. Chinese Pietersite has mostly striking gold, gold/red and gold/red/blue color segments (sometimes also including a deep golden brown color). While including some blues, these are mostly not the midnight/deep blue segments found more predominately in African Pietersite.
Regardless of the source, Pietersite will always have brecciated, fibrous bands of blue and/or gold and/or red Tiger Eye type fibers in quartz. The fibrous structure in Pietersite has been folded, stressed, even fractured and/or broken apart via the earth's geologic processes. The fibrous materials have then been reformed and naturally recemented together by Quartz, (Note: stones and crystals that go through this process are referred to as brecciated) creating a finished product with multiple colors, hues and superb chatoyancy.
While Pietersite has the lovely chatoyancy of Tiger Eye, it is not found in continuously structured bands or fibers, more in swirls, swathes and fibrous (sometimes linear) segments. Thus the structure of the fibrous streaks in Pietersite may appear rather chaotic, and can flow or exist in many directions side by side.
Colors include various blues, golds and reds, that may appear together or alone. The blues and golds in the stone tend to be the most intriguing. The blues range from a baby blue to a dark midnight hue, the golds can be light to very deep and rich, sometimes having a reddish hue, however, all fibrous color variations will have a superb and striking chatoyancy. CHATOYANCY is the appearance of a bright and subtly changing shimmer of color that moves along the surface of a gemstone as it is viewed from varying angles.
) Silicon and Oxygen, and has the chemical formula Mn2+3Al2(SiO4)3 (I know you were curious!)
Grey slate.. the Mother of All Dial Materials. 
