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Identity HelpHydrogrossular Garnet vs Idocrase(Vesuvianite)

5th Mar 2012 03:52 UTCram sati

In West Sumatra in the regencies of Dharmasraya and

Solok Selatan there is a massive deposit of a usually

green colour stone(from yellowish to green) that I always

believed to be Idocrase;there are also finds in the rivers as boulders

as well as in the mountains

I tested in different laboratoriums and I got different results

2 labs say is Idocrase

2 labs say is hydrogrossular garnet

So I am really confused of what could it be

Maybe both minerals in the same rock?

If you make a search with google just search by

Batu Sungai Dareh(this the local name of this stone)

so you can see some pictures

Could it be Tsavorite?

Some pictures I uploaded to Flickr

http://m.flickr.com/#/photos/23431216@N06/sets/72157629050107877/

Best regards

Alex

5th Mar 2012 19:45 UTCJosé Zendrera 🌟 Manager

Hola Alex,

Your question is not easy to answer, can see there is not many posts in this thread. Analytical results are perplexing. Although its crystal structure is similar, idocrase and grossular should be distinguishable in XRD analysis.

Without knowing the area, my impression points to idocrase, don't ask me why.

Once resolved this issue, we could take care to identify the red mineral that appears in some of your photos...

Greetings

5th Mar 2012 20:58 UTCErik Vercammen Expert

Vesuvianite and (hydro)grossular are both formed in skarns and can occur together.

15th Mar 2012 15:35 UTCram sati

Gracias José

Thanks Erik

Yes It's difficult here to find a gem lab in jakarta

who uses x-ray difraction

I should test better in a geology faculty lab maybe

in institute geology Bandung better than in a

gemologist

Best regards and thanks for replies

Alex Escobar Mercadal

16th Mar 2012 17:27 UTCram sati

One of the labs give me one reason why it's

not vesuvianite but hydrogrossular garnet and

this reason was that it has never been found

Crystals but allways massive and vesuvianite

allways found cristals in other localities in the

world

But as I read in some book in California the

Vesuvianite(Californite) never been found crystals

also but massive

Could be Idocrase also found as boulders in the

rivers?because in dharmasraya both places

is found this stone with very similar characteristics

being the one from river more translucent and

of some yellowish green colour

The area where are found is in Dharmarsya and

Solok Selatan in the highlands of Sumatra

Sane area there are iron mining,manganese mining

,gold mining,also found lot of garnet...

Mother stone of this mineral are skarns

Through these highlands cross the great Sumatran

fault and there are a few volcanoes,but the volcanoes

are some 4 or 5 hours away by car from location

of this stone

The boulders found in river batangharis that

starts in dharmasraya highlands and runs down

all through Jambi to meet the sea at malacca strait

Jose,the red stones that appear together with

some Idocrase? are jasper(I think)

This stone(Idocrase,hydrogrossular garnet or

whatever it is) is found most in green colour there

but also all the range from strong green to yellow

,pink and white

Just do a search by the name 'batu sungai Dareh'

in google or Idocrase sungai Dareh to see images

of it

They called locally Sumatran Jade but until

labs told Idocrase (but a few hydrogrossular garnet)

Best regards

12th Apr 2012 05:26 UTCEzekiel Hughes

Idocrase is what it looks like to me...some is probably the grossular and diopside is probably in all the stones....each particular stone is likely a mix..but idocrase is what is most likely prominent. For example, "Californite" is idocrase +/- "hydro-"grossular garnet....but they also have hydro-grossular ...but it is white, not green.

If you post some high quality pics on this Facebook site, we have a guy who has been testing (xrd) these stones and can give you a better answer than I can...may even test some for you.

http://www.facebook.com/groups/103080216397469/

30th Jun 2013 20:17 UTCal datuk sibungsu

Saya Al Datuk Sibungsu domisili di Padang Aro,Solok Selatan dalam beberapa tahun ini saya sangat antusias dan asyik menikmati keindahan Idocrase atau lumut Sungai Dareh ini.Saya siap bertukar informasi dan siap menanti serta menyambut kedatangan kawan Gemologist.Call me at 08526393288 atau pin bb saya 29e59cc7

30th Jun 2013 20:23 UTCal datuk sibungsu

Sorry 085263932888

1st Jul 2013 15:18 UTCDan Costian

To me it looks like jadeite.

6th May 2015 21:11 UTCNaveed

Ezekiel Hughes Wrote:

-------------------------------------------------------

> Idocrase is what it looks like to me...some is

> probably the grossular and diopside is probably in

> all the stones....each particular stone is likely

> a mix..but idocrase is what is most likely

> prominent. For example, "Californite" is idocrase

> +/- "hydro-"grossular garnet....but they also have

> hydro-grossular ...but it is white, not green.

>

> If you post some high quality pics on this

> Facebook site, we have a guy who has been testing

> (xrd) these stones and can give you a better

> answer than I can...may even test some for you.

>

> http://www.facebook.com/groups/103080216397469/

6th May 2015 21:15 UTCNaveed

I like your answer I think so

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