Time to catch up on reading, lapidary projects and binge watching TV. Stay home. Stay well.
Welcome to the GemologyOnline.com Forum
A non-profit Forum for the exchange of gemological ideas
It is currently Mon May 25, 2020 8:34 pm

All times are UTC - 4 hours

Post new topic Reply to topic  [ 1 post ] 
Author Message
 Post subject: The Austrian Emerald Story - Without Formating Problem
PostPosted: Fri Dec 16, 2005 6:10 pm 
Gemology Online Veteran
User avatar

Joined: Thu Nov 24, 2005 6:14 pm
Posts: 640
Location: Hohe Tauern N.P., Austria
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
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
Mixed crystals of the Kalifeldspars mostly Microkline and Adularia

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…

Although my English is not the best (Especially when it comes to the translation of mineral names) I hope to have given you an idea about the austrian emeralds. Unfortunately I can´t take inclusion photos properly, since my microscope has no camera port. As soon as I find a cheap one I will shoot some inclusion photos.

All the best from Austria


Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 1 post ] 

All times are UTC - 4 hours

Who is online

Users browsing this forum: No registered users and 1 guest

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
Gemology Style ported to phpBB3 by Christian Bullock