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Emeralds from Austria

  • Austria
 
View down Habach Valley
Said to have been known since the time of the Romans, there is an occurence of emerald in a very inaccessible spot some 2300 m above sea level, on the east side of the Legbach ravin, a branch of the Habchtal, in Salzburg, Austria. The occurence is of little importance, but mining by irregular methods has been carried on intermittently through the years, and in 1937 the mine was reopened on a small scale. Since WWII some crystals have been seen but whether these are from the 1937 working or from a resumption mining since the war is not certain. The simple hexagonal crystals are found in a mica and chlorite schist, a type of mother rock similar to that of the Uralian source. Thus the inclusions seen in the Habachtal emeralds are in general similar in type to those seen in the Russian emeralds, that is tremolite rods and mica plates with rounded outline. The SG of the Salzburg emeralds approximates to 2.73 and the indices of refraction are ordinary 1.591 and extraordinary 1.584, showing a birefringence of 0.007.
Although the occurrence of Emeralds in this high alpine valley is the only relevant one in Europe, it is of no importance in the international market. Most likely you will never have an Austrian emerald coming by in your everyday work. But some interesting differences to other gemstone deposits and mines like you know it from your areas lead to a myth that has formed around these gems.

1.) The History

The first written documents mentioning emeralds from this region date from the year 1669.
But it was proven by analysis (There is a link in the “Old mine colour” post of Richard related to that) that emeralds were already found in the region hundreds of years before that time.

The longer you go back in time, the more beautiful the gems: There is a Monstranz (I don´t know the English word for it, It is a catholic sacral object holding the consecrated wafer) in a monastery about 100 km north of the mine in which 12 beautiful rough emeralds up to 9 cm in length are mounted. There are only old black and white pictures of the piece, the monks dont show it to the public anymore and it is, understandingly, kept in a bank safe. I try to convince them since a few years that a better documentation of these fantastic gemstones by experts would be in their own interest.

Through the fact that the emerald hosting rocks are situated in 2.000 to 2.200 m above sea level in extremely steep mountains, it was not possible to establish a mine for a very long time. Thanks to the climate change the actual primary deposit is free of ice for about 3 - 5 months a year and it may have been covered with snowfields all year long back in the 16th century.

Avalanches, rolling stones, missing street connections, landslides and high flash floods always kept people away from this area, which nowadays is a national park called “Hohe Tauern”.

The first bigger international appearance of Habachtal emeralds was in 1861 at the London world industrial exhibition. The stones were so beautiful that a Viennese jewellerer invested a lot of money in opening a mine up there. He was successful, one of the gems he mined in that period was 42 carats after cutting and is now mounted into the English crown jewels.

Later on an English company (Esmerald Mines Ltd.) took over the operations for about 20 years, and the stones they mined in that period (There are only figures for one year left in documents: in the 1903 season they sent 32.000 Carats of fine rough and 7.000 Carats of best quality to England) were labelled as “Indian emeralds”, because the deposit was not known to most of the people in gem trade and would have sold for a much lower price.

The first world war (England and Austria were opponents) set an end to that profitable mining period. Before the English were forced to leave, they blew up the so called “emerald breast” a geological formation within the mine were the best gems were found. This rich mother lode is still undetected nowadays, wich adds another piece of puzzle to the myth of Habachtal.

All following mining operations up to the present time never repeated the success of the English period. Since the mine is in a national park, the authorities only allow methods of mining that are harmless to the environment. No machines (Except a generator for electricity to light the tunnels) are allowed and they are only allowed to extract 50 cubic meters of mother rock per season. Everything is done by hand. Most pieces were and are sold as mineral specimens. The family that runs the mine today generates good money with these specimens, but only about 20 to 50 emeralds per year are clean and big enough to match up with the best colombian gems.

Here is another interesting difference to international emerald market: All cut and polished emeralds from Habachtal are sold for double (Poor qualities) to triple (The best gems) the price of comparable Colombian material. These high prices are paid by European collectors only, but paid is paid.
Some people tried to take advantage of this fact and imported cheap rough from other mines around the world to sell them as Austrian emeralds.
These betrayals were uncovered very fast, since the inclusions of Austrian emeralds make them easily identifiable to gemmologists.

2.) Mineralogical and geological overview of the deposit

The main reason for the low share of facettable material to be found is the geological process that led to the crystallisation of the emeralds.
They all grew inside the mother rock as porphyroblasts and although the region is full of alpinotype caves filled with beautiful crystals (More than 120 different minerals can be found in the Habach-valley) there were no bigger findings of clean emerald crystals in such pockets.

The emerald hosting mother rock is a series of layers built up by talcum, mica schists (Biotite and Muscovite) and banded gneisses. This series of layers formed at a tectonic contact zone of two huge geological complexes that were transported down into the earth´s crust within the formation of the alps and later on folded up again. The Habachtal is the type-locality for the emerald deposit type “Schists without Pegmatites”.

One of the complexes brought the beryllium, the other one the chromium and as the rocks were “cooked up” the green beauties crystallized under great pressure within the mother rock.

As a result of that growth within the rock , austrian emeralds are hosting a wide variety of crystalline inclusions. When observing them carefully, these emeralds can easily be separated from other origins.

Another interesting mineralization a few hundred meters above the emerald formation is the occurrence of Phenakites. These Phenakites are the biggest ones to be found in Europe. Some of them are above 50 Cts. after cutting and they are very much sought after by collectors.

3.) Inclusions

List of Minerals found as crystal inclusions within emeralds, aquamarines and beryls of the deposit:

Sulfides: Pyrite,Pyrrhotine, Chalcopyrite, Molybdenite,Pentlandite
Oxides: Magnetite, Ilmenite, Rutile, Anatase, Brookite
Carbonates: Calcite, Dolomite
Tungsten: Scheelite
Phosphates: Mixed crystals of the Apatite group
Silicates: Mixed crystals of the Biotite-Phlogopite row
Muscovite
Beryllium-Margarite
Mixed crystals of the chlorite group
Mixed crystals of the Tremolite group
Mixed crystals of the Epidot-group (zonar growth) often Epidot, Klinozoisite, Allanite and Zoisite
Mixed crystals of the Plagioklase group (zonar growth) mostly Albite and Oligoklase
Mixed crystals of the Tourmaline-group (zonar growth) mostly Dravite and Schorl
Talcum
Titanite
Zircons
Mixed crystals of the Kalifeldspars mostly Microkline and Adularia
Phenakite

There were a few other minerals found as an inclusion but those were only detected with instruments a normal gemmologist has no access to.

4.) The myth is alive

Many European mineral collectors go for vacation to this valley every summer to dig for the secondary deposited emerald crystals. I also do that since I was a child. It is my definition of adventure. In difference to other regions of the world, where poor miners work hard for a few pennies because they have no other choice, in this area lawyers and doctors with a mineralogical or gemmological hobby background invest their precious time for the unbeatable adrenaline kick you get when a traffic light green gem glows in the mud. Even if a majority of crystals are of nearly no value.

The crystals are washed out of the mud under the mines entrance. Since the mother rock only has hardness 1 after Mohs the water unearthes the relatively light emeralds and transports them downwards. Into our hands. The majority of the crystals we find is good in colour but poor in clarity. I would estimate that about 1 of 100 emerald crystals found is of cutting quality. Another problem is brittleness which is even higher than in normal emeralds. But most of the emeralds are never being cut, especially pieces of mother rock with emeralds bring a lot more money if you sell them. Most people never sell what they find…


Whenever one of you visits Austria in summertime, I recommend to go to the Habachtal for a few days. Beautiful landscape, many interesting people and a lot of fun when acting like little childs climbing and digging around covered with mud!

I find between 5 and 35 Emeralds a day when I dig there, and I know noone who went there and didn´t find at least one of them.

The biggest one I found (It is not cuttable but a mineralogic curiosity) was a 21,57 Carats conglomerate of 7 crystals that seem to be molten together. I always have it with me.

A few years before a mineral collector from the Netherlands found the best emeralds since half a century: Look at the Picture, these look nearly Colombian and there are 14 of them on this piece of rock. The biggest one is over 3 cm and they are very clear. I know people that would pay over 50.000,- Euros for that piece…

Emeralds from Australia

NSW rough and cut emeralds

Australia is not a significant producer of gem quality emerald; but it does have some interesting emerald deposits. Over the last century four deposits have been commercially mined for emerald: Emmaville and Torrington in New South Wales, and Poona and Menzies in Western Australia.

Read more: Emeralds from Australia

Emeralds and Advanced Testing with Raman and FTIR

FTIR
FTIR stands for Fourier Transformation Infra-Red, and it is a spectrophotometer in infrared region that can obtain absorption spectra with frequency analysis called Fourier Transformation on a waveform, which is obtained from a sample by illuminating it with a composite waveform that is made from light from a light source through an interferometer. By obtaining molecular vibration in a substance, FTIR can effectively analyse water, hydroxyl and resin or oil in crystals.

Read more: Emeralds and Advanced Testing with Raman and FTIR

Emeralds from Norway

Byrud Emerald Mine,  Minnesund,  Eidsvoll (Eidsvold),  Akershus,  Norway

 

INTRODUCTION

Located at the shore of Lake Mjøsa -Norway’s largest lake- is one of the very few European occurrences of emeralds in gemstone quality. The deposit was discovered around 1880. An English mining company - “The Norwegian & General Exploration Company LTD”- operated the deposit from 1899 till 1909. The mines were abandoned after only ten years of operation, due to the low productivity of the mines and the low quality of the emeralds.

Read more: Emeralds from Norway

Emerald Treatments

Treatments

As in other gemstones you may be surprised to learn that many gemstones are enhanced in some way or another. 95% - 99% of all emeralds are treated with a liquid or resin after cutting. Most are treated to improve the passage of light within stone. The physical makeup of the emerald crystal, with its tiny natural fissures simply makes it logical to do so.

Read more: Emerald Treatments

Who are we?

The Geohavens name is an assurance of timeless beauty, distinct quality and uncompromising value. The Company spares no effort in sourcing from the farthest markets and the deepest mines in order to unearth the most attractive gems.

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