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[Jhon P]

Here is a piece of chrysoprase from turkey. It changes color from wet to dry
How many different kinds is there?

[lithicbeads]

Many stones have large interstertial spaces between the rock grains and water can migrate into those spaces and improve translucency if the atomic structure of the stone makes spaces large enough. Ofet it is common in feldspars and of course hydrophane opal.

[Jhon P]

More chrysoprase ( motorite ) from Africa
And real chrysoprase from Australia

[southerly]

Technically chrysoprase is chalcedony where nickel minerals have cystalised in the gaps between cryptocrystalline quartz crystals in the chalcedony. Which gives the bright green colour. Any other green chalcedony is not chrysoprase. BTW I do not know of any Australian chrysoprase that absorbs or holds water.

Chrysoprase from Mt Davies on the South Australia/West Australian boarder


Chrysoprase with magnesite as well nickel in the chalcedony, shows how the chalcedony can grade in and out of chrysoprase, from Western Australia


My favourite, showing the grading from clear chalcedony, to chrysoprase and magnesite/chalcedony mix, this piece just glows




Chrysoprase from Malborough Queensland, arguably the producer of the finest chrysoprase in the world.

[gemfeller]

I think it should also be noted that Mtorolite from Africa and green chrome chalcedony from Western Australia are not chrysoprase.  They are both colored by chrome, as noted, not nickel, and are a different material.  Mtorolite is simply a trade name for chrome chalcedony. There seems to be a lot of confusion about that lately on the forums I visit.

Thanks for showing various types of chrysoprase from Oz Southerly.  I've been a great fan of the Marlborough material for many years.  I assume the stone below is from another location, maybe Mt. Davies?


 

[southerly]

I think it should also be noted that Mtorolite from Africa and green chrome chalcedony from Western Australia are not chrysoprase.  They are both colored by chrome, as noted, not nickel, and are a different material.  Mtorolite is simply a trade name for chrome chalcedony. There seems to be a lot of confusion about that lately on the forums I visit.

Thanks for showing various types of chrysoprase from Oz Southerly.  I've been a great fan of the Marlborough material for many years.  I assume the stone below is from another location, maybe Mt. Davies?

Could be WA chrysoprase, black dendrites are not common in the Malborough material. There are quite a lot of deposits in the WA nickel belt.

[southerly]

The South Australian dept of mining has a great article on the Mount Davies mines and chrysoprase formation in Australia in general.

http://www.minerals.statedevelopment.sa.gov.au/__data/assets/pdf_file/0010/240859/mj02_chrysoprase.pdf

[Jhon P]

I did say that the Australian was real chrysoprase!  I know that Mtorolite is colored with nickel and not true chrysoprase (but I still like it) I haven't been able to find out what colors the stuff from turkey. I just thought that it was interesting because it will absorb water and get dark green than over a few days it lighten up.
 I love to see these in depth conversations about rocks. Loved all of chrysoprase pictures keep them coming
 And here is another rock that is not true chrysoprase
Lemon chrysoprase a phosphate mineral 

[tntmom]

That carving is amazing Southerly!!!!  And I love the dendrites in other types of Chrysoprase.  I don't see them very often though :(

[Greg Hiller]

I picked up some great stuff with the dendrites in it a few weekends ago at the gem show in southern Cal.  I'm looking forward to slabbing some of it up. 

[olgguy]

I don't mean to question your post because you know where you bought the material, is there a possibility that it is a Variscite ?

[gemfeller]

Most of the so-called "Citron" or "Lemon" Chrysoprase being sold these days is actually the mineral magnesite.  Sometimes it forms the core of beautiful green chrysoprase (chalcedony) masses which make some very attractive specimens.  While the greenish-yellow material is natural, some types of magnesite are dyed to mimic turquoise.

This link is a good discussion of green chalcedony properties IMO.  http://geology.com/gemstones/chrysoprase/

This image, from the Outback Mining website, shows a chrysoprase slab with a yellow magnesite center:

[southerly]

Most of the so-called "Citron" or "Lemon" Chrysoprase being sold these days is actually the mineral magnesite.  Sometimes it forms the core of beautiful green chrysoprase (chalcedony) masses which make some very attractive specimens.  While the greenish-yellow material is natural, some types of magnesite are dyed to mimic turquoise.

This link is a good discussion of green chalcedony properties IMO.  http://geology.com/gemstones/chrysoprase/

This image, from the Outback Mining website, shows a chrysoprase slab with a yellow magnesite center:

Gemfeller is correct, note that pure magnesite is often soft and chalky from WA, the yellow centre in the example photo is magnesitite and chalcedony mix and therefore can be polished. The chalky magnesite is pourus and friable and not suitable to lapidary, it needs the chalcedony silica content to be useful.

[Jhon P]

Interesting!