Batu Sungai Dareh (Idocrase) and Filipus Kesuma

Several years ago in Sumatra I dumped into a shop in Pekanbaru,Riau of a Chinese man selling minerals and fossils;I bought him a stone that he said was Sumatra Jade from the Aceh region;it was really looks like jade;then I went into gem markets in Sumatra and many people where carving what they said to be sumatra jade;I bought many of low grade quality,I still did not seen the upper gem grade;then I was back into Spain;couple of years later I went back into Sumatra to West Sumatra where I met a chinese man who was carving what many people believed to be jade;he told me it was not jade but Idocrase,then he showed me a high grade cabs and they were really stunningly beautiful;the price in indonesia it was quite high and almost every indonesian in the gem markets were using a big stone ring from this stone that they call Giok Sumatra(sumatra jade) and also known locally as Batu Sungai Dareh(stone from river Dareh) for the locality where it was first found in west sumatra;later I went into more reaearch about it and discovered it comes out from two regencies of west sumatra near to mt wife's vilage;I bought many from my chinese just made friend and I brough into a gemlabs in Jakarta where they confirmed me to be Idocrase(more commonly known as Vesuvianite in the mineral world),then I tested more samples in other gemlabs also in jakarta and the result was Hydrogrossular garnet from what I have the conclussion that it is Idocrase with some hydrogrossular garnet in it;the more whitish the colour the more hydrogrossular garnet in it's composition and the more green trasparent the more idocrase proportion:;most of it is idocrase,some hydrogrossular garnet and some are a mix of both minerals;they usually come as deposits in limestones and also as boulders in the rivers in remote areas of the hills on central sumatra in the west sumatran province;there is no big explotation of this mineral,just some locals extract it in a very remote areas and sell to local carvers.

This stone was already exported to the middle east in the 80's by Tommy Soeharto,son of former Indonesian president Soeharto as he had a palm oild plantations in the area of Dharmasraya(one of the regencies where idocrase comes out from),he exploited that until the close to the villages deposits were finished and nowadays the villagers who mineit walk more than 100 km inside the jungle and uphill to find it.

Idocrase from the west sumatra area most of it is massive green colour but also can be found a very few in another colours like pink and orange and black and white

It is a Tetragonal Silicate(space group P4/nnc);the general ideal formula for Vesuvianite or Idocrase is:

Ca19(Al,Mg,Fe+2)13Si18O69(OH,F)9

The structure is very similar to that of Hydrogrossular Garnet and to distinguish one from each other is necessary an X-Ray difraction test

Depending on the type and the amount of Chromophores present in a cristal,vesuvianite can be colourless to pale yellow,pale pink to deep red-purple(Mn+2,Mn+3),yellowish green(Fe+2) to rich emerald green(Cr+3),bright blue(Cr+2) to blue green(Cr+2 and Fe+2) and brown to black(Ti+4)

In Sumatra it comes generally in deposits in metamorphic rocks like skarns,limestones,serpentines...but also as I told before as boulders in rivers and specially in Batanhari river that starts in Dharmasraya in west sumatra and runs down through all jambi province to finally met the sea at malacca Strait.

All the Idocrase I have is carve abd cut by my good friend in Padang,West Sumatra capital by Kwee Goan Siong,an indonesian-chinese ethnic and a very skilled carver and collector of stones;I wish to be able some jewelry designers use it in their designs and would become more known in the gems trade 

There is not also huge deposits in sumatra,is very much difficult to get a upper grade and to get a big enough cab and with good traslucency because of the natural creaks of the rock and sometimes opacity;a big carat size with good trasparency and colour demands high prices

The most rare ones are the pink colour that demand around 400$ a carat but for the other colours it ranges from 10$ a carat to 200$ a carat depending on quality

Tsavorite garnet from Tanzania and Kenya is a grossular garnet that is very high end prize,as Tiffany's and company make a big marketing campaign when it was discovered,before no one knew about tsavorite but after tha marketing by Tiffany's the prize skyrocketed to thousands of dollars a carat;I think Idocrase can have a similar process with the years passing by(Hydrogrossular garnet,idocrase and tsavorite are very close related)

In modern jeweller magazine you can read an article about hydrogrossular garnet and it's price:

http://www.modernjeweler.com/publication/article.jsp?pubId=1&id=802&pageNum=2

Then I gemval to make an appraisal of the stone and know an average price:

http://www.gemval.com/index.php

This is Filipus,Willy and Om Feri looking for stones at a river in Tarusan,Pesisir Selatan
We wnet there for the day hunting stones,that area is the area where my wife comes from,Tarusan

Filipus Kesuma in action,he found a beautiful Jasper

Some red jasper

Jembatan akar(root bridge),is a bridge formed by the roots of 2 banyak trees at each side of the river in an area called Bayang in Tarusan,around 4 hours from Padang city
2 days before a tiger was falling down from the cliffs surrounding this area,the locals sacred a lot as fell to the pavement on the road,they called someone from local government and a vets coming to bring the tiget and heal him,some weeks later was released again in the jungles around here

Root Brige in Bayang

We found this beautiful friend in a palm tree

Just 20 minutes from my wife old family house

Tarusan beach

Idocrases from Dharmasraya

The great Filipus Kesuma and his son

Idocrase aka batu Sungai Dareh;sungai dareh is a hamlet in Dharmasraya and is where idocrase  was found the first time;Filipus told me story it was found by children in th erivers and they brought to Padang,sso people started to call it Batu Sungai Dareh(Batu means stone)

Filipus Kesuma aka Kwee Goan Siong

After a hunting stones day Hmmm delicious Durian,the king of fruits in Indonesia and south asia

Filipus with Om Sinyo
Om Sinyo is Singsei,a traditional chinese medicine man;he is originally from Batusangkar
He treated my head shoulder fracture;I had fallen in the river and fractured the humeral head into 4 fragments and I refused to get an operation and put a pins in a hospital;now I fell quite recovered but only that I lost some degrees of movement only 

Filipus in his brother's house