Wednesday
Oct012003
Jade News - Fall 2003
Wednesday, October 1, 2003 at 08:48AM
Fall 2003
Dear Friends of Jade!
Here some news on Jade I collected this summer and fall and which I want to share with you.
1. Another green takes over!
In September this year I had the pleasure to show also to Doug Nichol (Wrexham/UK) the Nephrite site in Val Faller in Switzerland. Doug is preparing a book on European Nephrite Geology and wanted to see first hand the site reported by Welter in 1910. As you have seen in my previous communications, the aspect of the nephrite pod (Site 2) has been documented by Welter in a sketch based on a picture his colleague Mr. Bancroft took during their visit. During the visit of Doug, and having the original sketch of Welter at hand, we tried to take a picture as close as possible from the same vantage point. Below you see again the overall view of the Val Faller road looking south, with the original iron fence posts and the nephrite pod site. The most striking difference between the 1910 and 2003 view of the Nephrite site is the strong overgrowth of the pod with grass and threes and also the very strong weathering of the Nephrite.
View of Val Faller road at Nephrite site 2
View of the front end of the Welter nephrite pod showing extensive weathering to white powder
Welter 1910 sketch and the same site 2003 showing overgrowth and the remnants of the same path across the pod
2. The Scortaseo site saved?
During the visit in April this year to the Scortaseo/Poschiavo/Switzerland “Troutstone” Nephrite site with Russel Beck of New Zealand, we had noticed that the limestone/dolomite and nephrite boulders of the ancient Talcum mine were transformed into road building gravel. In September however all rock crushing material was gone and it can be hoped that only the tooth of time and not the hand of men will obliterate the site. There are still plenty of nephrite boulders left over for mineral collectors and local craftsmen.
Scortaseo site now devoid of rock crushing equipment and a left-over “Trout-stone” Nephrite boulder.
Jade beads necklaces and ear-pins made by local craftsmen out of Scortaseo Nephrite
and local pink marble.
3. A new Nephrite Jade site in the Italian Alps!
At the IV Symposium of FEEG - Federation for European Education in Gemmology, held in January 2002 in Vicenza/Italy, Dr. V. de Michele of the Gemological Institute of Italy reported on “Nephrite from Val Malenco”. Doug Nichol and I were eager to get further information on this new site and as we were nearby in Scortaseo, we crossed the border into Italy and visited Mr. Pietro Nana in Sondrio. Mr. Nana has a mineral and precious stone jewelry shop there and gave us first hand information on his discovery of the site and showed us his trove of rough material and carvings and necklaces made from it.
The Val Malenco valley, located in a mountainous area near the Italian/Swiss border, is a text book example of mountain building geology and at the very joint (Insubrian line) where the African Plate, drifting northwards, pushed under the European Plate and caused the uplifting of the Alps. The valley and the surrounding areas are very famous for its vast variety of minerals of which over 200 are found (http://www.novanet.it/vvol/ambiente/mineralogia/) there.
Key minerals extracted industrially are Serpentine, Talcum, Steatite and until the 1970’s, also asbestos.
The events leading to the discovery of the Val Malenco Nephrite Jade have striking similarities with that of the Scortaseo Nephrite Jade, with both sites at a distance of less than 20 Km as the crow flies (see map below).
Map showing the Scortaseo/Switzerland and the Alpe Mastabia/Italy Nephrite-in-Talcum sites
Like Mr. Jochum in Poschiavo, Mr. Nana in Chiesa/Val Malenco has passed dozens and dozens of times at the site where deaf material of a Talcum mine was discharged down a slope. Only their professional interest in minerals led them to take a closer look at these “useless” rocks as, after a heavy rain shower, the white coating of leftover Talcum rock has been washed away and a greenish translucent body was revealed.
Whereas the Poschiavo material has pea-sized Nephrite beads embedded in a Calcite matrix, the Val Malenco Jade has a singles phase structure of the same pale whitish green to greenish yellow color. Both sites are ancient talcum mines with no direct contact with serpentine although steatite or soapstone or pietra ollare, as called locally, is found not far from the Val Malenco site.
The Nephrite is located near the center of the Talcum vein and has about 30-50cm thickness with a symmetric progression from Dolomite rock to Talcum to Tremolite to Nephrite Jade (ferriferous Tremolite).
The Val Malenco Talcum/Jade mine, located at a height of 2200m on the Alpe Mastabia, slightly west of Chiesa in Val Malenco, is now caved in/closed down due the presence of dangerous amounts of Tremolite fibers causing health problems during Talcum extraction..
Mr. Nana has been able to collect whatever Nephrite containing material was still lying around. The actually available quantity is guessed to be less than few m3.
The best pale green to yellow apple green material is transformed by Mr. Nana in Germany and in China to bead necklaces and small animal carvings. Only about 30% of the rough material results in finished beads.
By carefully grading the color tones of the beads from a more grey greenish to a soft yellowish green and assembling them into color matched necklaces, he seems to have caught the eye of Italian ladies and sells them between 250 to 700€ (≈US $) a piece. He mentioned that the wife of the Italian President wears one of these Val Malenco Jade necklaces.
One of Mr. Nana’s Val Malenco Jade necklaces in his shop
Mr. Pietro Nana and Doug Nichol with a piece of Val Malenco Jade
Scortaseo pea-like Nephrite and Val Malenco massive Nephrite at the same magnification
Fracture surface of a Val Malenco nephrite rough showing color graduations
from a whitish apple green (1) to a yellowish fatty green (2).
The Val Malenco Nephrite is characterized by having a) parts rich in original straight Tremolite fibers giving it a slightly chatoyant aspect and b) fist sized nodular regions of an intense yellow-green fattish color.
Chatoyant Tremolite fiber rich section of Val Malenco Nephrite
4. What the heck will you be doing in Itoigawa?
This has been the question my Japanese colleagues asked me, when attending a scientific meeting in Yokohama in October; I told them that I will be traveling to Itoigawa on Japans West coast.
But You, Friends of Jade, know that around Itoigawa the world oldest Jadeite using culture flourished in the Japanese Jomon (straw rope pattern ceramics) period from about 4000Bc to 1600BC and I did not want to miss the opportunity to visit the sites where massive Jadeite boulders are found (See also Jade in Japan in Jade by Keverne 1991 p216-217).
I have received valuable information on how to get there and whom to contact locally by Russel Beck, which had visited the area few years ago and which I want to thank for the valuable hints.
Itoigawa is a small town with about 30.000 inhabitants in the Niigata Prefecture on the west coast of the main Japanese island of Honshu facing the Japanese Sea and, by using the double-decker Maxi Toki Shinkansen via Echigo Yuzawa and Naoetsu, about 3h away from Tokio.
Itoigawa is situated at the western edge of the Japanese Alps which peak locally with Mt. Korenge-Yama at 2769m. The area around Itoigawa is geologically extremely interesting as it is the western end of a late Cenozoic subsidence that has a thick sequence of sediments and volcanic rocks and that cuts, 300km long and about 50Km wide, across central Honshu. The youngest rock near Itoigawa is barely 1000 years (on Mt. Yake-Yama volcano) and the oldest 350 Mio years old (metamorphic rocks containing jadeite). This subsidence has been named Fossa Magna (big trench) by German geologist Dr. E. Naumann which, from 1875 to 1885, was professor of Geology at the University of Tokio and, as founder and the first head manager of the Geological Survey of Japan, studied its structure and extent.
The western rim of the Fossa Magna is the suture line between the Eurasian and North American plate and also called the Itoigawa (Sea of Japan) – Shizuoka (Pacific Ocean) Tectonic line. Along this line rapid uplifting formed the Japanese Alps in the Pleistocene (2 Mio years BC). This tectonic movement carried up and exposed Serpentinite which contained massive Jadeite blocs that have been dated, by the included Zircons, to be about 450 to 500 Mio years old.
The presence of massive Jadeite makes Itoigawa the main area in Japan where to look for this mineral although at several more sites in Japan Jadeite can be found in smaller quantities.
Key sites where massive Jadeite can found in the world and in Japan
5. 4000 BC Neolithic Jadeite culture in Japan!
The Jadeite from the Itoigawa area was used in prehistoric times by people of the Jomon culture (4000 to 1600 BC) for fashioning first tools and then beads and pendants (taishu’s) and later on also the well known comma or cashew shaped Jade pendants or Magatamas. A Neolithic Jomon settlement has been excavated on Myama, a small hill overlooking Itoigawa City and all the artifacts assembled in a newly build museum the Chojagahara Archeology Hall. Jadeite use died out in Japan around 700 AD.
Jomon village excavation site at Itoigawa and welcome sign in the Museum area
Display of Jomon culture Jadeite artifacts in the Chojagahara Archeology Hall.
The lower left picture shows the leftover of an aborted Neolithic drilling attempt carried out probably with a bamboo drill bit and abrasive sand.
Test showed that a penetration rate of 1mm per hour could be thus achieved.
Further ornamental Itoigawa Jadeite artifacts consisting of slit ear-rings (1), Taishu (2) and Kudatama pendants (3) and an odd shaped Magatama (4)
Map showing sites in Japan where jadeite artifacts of the Yomon, Yayoi and Kofun cultures were unearthed as also an insert of the Itoigawa Jadeite area.
The short visit to the museum and the wealth of prehistoric Jadeite in Japan makes it imperative that any further new compendium or book on Jade should include also a mayor section on geology and archeology of Jadeite in Japan.
6. Jadeite heaven in Itoigawa!
The fact that the Itoigawa area is a geological very varied region with plenty of Jadeite and the famous Fossa Magna Tectonic through led the local government to establish in 1994 a focusing point for all these treasures, the Fossa Magna Geological Museum.
I had the pleasure to be shown around through its excellent and well presented collection of minerals in general and Jadeite in special by Curator Dr. Ko Takenouchi ().
Fossa Magna Geological Museum in Itoigawa with a 4 ton Jadeite welcome boulder
Dr. Takenouchi showing me the Fossa Magna Museum Jadeite treasures such a cobalt blue (not lavender!) Jadeite
Typical Itoigawa Jadeite samples
An exceptional piece of translucent white-to-emerald green Jadeite in the Fossa Magna Museum.
A fully translucent Jadeite boulder section with Titanium induced blue colors in the nearby Omi Natural History Museum
The Jadeite of Itoigawa is associated with the uplifting structures of the Japanese Alps during which several narrow band of Serpentinite protrusions were carried to the surface and eroded away exposing the embedded Jadeite blocs. Jadeite itself is formed at medium temperature (200-400°C) - high pressure (5-7Kbar) conditions corresponding to a depth of between 16 to 20 Km by either vein crystallization from geothermal fluids or by partial metasomatic replacement.
The two main deposits of large Jadeite boulders are found in areas where the Omi-Gawa (1) and the Kotaki-Gawa (2) rivers intersect two narrow bands of Serpentinite about 5 to 15Km south-east of the coast line. The first in-situ find was made there in 1939 and, whatever Jadeite is left at both sites, is now protected as two small natural park since 1956. Nephrite is also found in the Hime-Gawa River (3) and along the shoreline in Itoigawa.
Omi River and Kotaki River Jadeite protected areas south-east of Omi and Itoigawa town.
Geological map by Chihara et al.(1979) showing the narrow banded Serpentinite areas around Itoigawa intersected by the Omi-Gawa (1) and Kotaki-Gawa (2) rivers
Although the areas south-east of Itoigawa abound with Serpentinite assemblies, according to Dr. Takenouchi, Jadeite is only present in those places where Serpentinite is present as very narrow (<100m) squeezed bands. Jadeite boulders are eroded out from them more easily when per chance a river, as in the case of the Omi and the Kotaki River, disect such strata. A detailed description on the relevant geological features associated with the Omi and Kotaki Jadeite deposit can be found in English in “Jadeite in Japan” by K. Chihara in the Journal of The Gemmological Society of Japan 20 (1999) p 5-21 and the associated references. Dr. Takenouchi took my by car to the Kotaki River or Hisui-Kyo (Jade ravine) site situated at the foot of the 2077m Myojo-Yama Mountain. The gorge is situated at 36° 55’ 33N and 137° 49’ 19 E at about 260m above sea level.
Kotaki River traversing the Hisui-Kyo or Jade ravine in full fall colors.
Explanatory display at the protected Jadeite site on the Kotaki River with the exact location of the remaining 50 boulders of Jadeite shown in red.
The white looking Jadeite boulders range in size from about 50cm to 4m and are interdispersed with red Sandstone and white Limestone boulders.
The site has become quite a tourist attraction and a nearby shop, as also shops in Itoigawa itself, sell small quantities of natural shaped and polished Itoigawa Jadeite at about 25 to 50$ per Kg.
As the supply of indigenous Jadeite is limited, the major part the exposed Jadeite or Hisui items are however in Myanmar (Burma) Jadeite. The local merchants buy Myanmar material mostly in the color and structural pattern closely resembling that of Itoigawa material so that you need a trained eye to get the right stuff.
At some of the Jadeite boulders in the Kotaki River bed
Water worn Kotaki Jadeite boulder surface
Polished Boulder section Polished Kotaki Jadeite slab acting as table top in the Tea House of the Tanimura Museum in Itoigawa showing white Jadeite seemingly floating in a ”green” matrix. Noticeable are also rich emerald green areas where the green phase is more dilute.
Local Rock collectors selling their Itoigawa Jadeite pebbles and boulders at the Oyashirazu Pier market at about 5.000 to 20.000 ¥ or 50 to 200$ per pebble.
102 Ton Jadeite rock from the Omi River located in the Jadeite boulder “museum” at the Oyashirazu Pier market. The boulder is mostly of white Jadeite with areas of green and blue. Many thanks go to Mr. and Mrs. Mitsui Sunada and Dr. Ko Takenouchi for the kind hospitality in Itoigawa and sharing with me their Jadeite knowledge. Zürich 1.11.2003
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