FMF - Friends of Minerals Forum, discussion and message board

[Tsinidis Tasos]

Hello!
This is a "rock" consisting of rhodonite,garnet (andradite) and californite (light green encrustation).It was found at a skarn zone as a lens-shaped form inside an altered "garnetite"rock.All the geologists,collectors and mineral dealers i asked told me that they had never seen or heard anything like this.
Can you please tell me if you have seen or know anything like this?It would be very nice if i find out that i have a rarity!
The total weight of the "rock" found is about 10 kilos.
The specimen shown below is the bigger with size 13x8x5 cm.
Thank you!

[John S. White]

All three of these minerals are commonly found in contact metamorphic rocks as this one appears to be. Californite is, of course, a varietal name for vesuvianite, the preferred name. How sure are you of the identification of the garnet? Since rhodonite is a manganese mineral, I would expect an associated garnet to be spessartine and the other mineral may actually be manganvesuvianite. In any case, it is a lovely rock and a specimen that any serious collector would be pleased to own.

[Tsinidis Tasos]

The identification of the garnet in this contact metamorphic zone was made during a geological research for wollastonite occurences in this area.The exact words of the analysis text about garnets are :..."the garnets are composed mainly of andradite- grossular (andradite 49%)...".By reading this i assumed that i can call this garnet
"andradite". Please correct me if i am wrong!
The identification of californite was made by a geologist of the Geological department of Aristotle University of Thessaloniki.

[John S. White]

If you have data that indicate the garnet is andradite, then it would be presumptuous of me to try to tell you that you are wrong. I find it odd, however, that a garnet intimately associated with rhodonite would not be a manganese-rich or even a manganese-bearing garnet instead of a Ca-Fe-Al garnet. I am not saying that this is impossible, but it does appear somewhat unlikely.

This anamoly makes your rock even more interesting.

The name californite really ought to be abandoned. It is a variety name only but it does imply a green compact form so I can see why the university geologist used it. My recommendation for your label would be something like this:

vesuvianite (var. californite)