[Rockhounds] when volcanoes drop bombs: giant crystal payload

[John Junkroski]

This sounds very much like a site we visited a few weeks ago after  
digging at the Spencer opal mines.

A local gentlemen suggested that we drive out and assured us that  
access was no problem since the local road commission was using the  
cinder cone as a source for road-fill.

We spent the better part of an hour exploring three or four recently  
active pits and found nothing other than a few 1/4 inch  yellowish,
opaque crystals that I could not identify. I picked up an awful lot  
of (boring) black basalt and found nothing worth bringing home.

If anyone has any suggestions on how to locate the "sunstone"on the  
cindercone I would greatly appreciate hearing them, as we intend to  
go back to Spencer early next Summer.

Opal is great fun, and the people at the Spencer mine are wonderful  
hosts.

John

On Aug 1, 2007, at 10:54 AM, Tim Fisher wrote:

> Whoops, my bad I was thinking of another site. Anyway its Cinder  
> Butte, SE of Spencer, and it's in Lanny's book. If it's sunstone  
> it's automatically plagioclase, at least until some was analyzed  
> and found to me andesine lol.
>
> At 08:30 AM 8/1/2007, you wrote:
>
>> Pmodreski at aol.com wrote:
>>
>>
>>>
>>> In a message dated 8/1/2007 8:06:12 AM Mountain Daylight Time,
>>> nospam at orerockon.com writes:
>>> It's  sunstone, it is from a well know collecting site on a  
>>> cinder cone in WY  just over the ID border.
>>> Ah, but sunstone is a descriptive term, is it sanidine or  
>>> orthoclase?
>>> Probably orthoclase.  Don, the master feldsparologist, will  
>>> certainly find  out.
>>>
>>
>>
>> Holy cow, what a way to start the morning.  OK, in sum, I can say  
>> the gentleman definitely found it in Idaho; so perhaps there is  
>> more than one volcanic field with this type of formation?  I never  
>> had volcanology so I don't know if this could have blown that far  
>> from WY.
>>
>> The geologist who is working with these kept calling them  
>> plagioclase. But there is no point in speculation or pontification  
>> until we get a chance to look at them.  He had some of them  
>> prepped for mass spectrometry so I suppose he'll know the trace  
>> elements and REEs soon.
>> I will try to x-ray them today but maybe someone else is using the  
>> instrument.
>>
>>
>> Don
>>
>
> Tim Fisher
> Ore-ROCK-On!
> Email address at http://OreRockOn.com
> -- 
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