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Actinolite

Posted by Rock Currier  
avatar Re: Actinolite
March 18, 2009 10:09AM
Harjo,
Why don't you see what you can do with Millerite on a world wide basis. That is not too big a mineral and when you get that one done, ill put you up for moderator of the best minerals forums.

Rock Currier
Crystals not pistols.
avatar Re: Actinolite
March 18, 2009 03:23PM
    
I'll have a look at it this evening Rock.
avatar Re: Actinolite
March 31, 2009 11:29PM
I am surprised there is no Australian actinolite showing - there are good specimens from Arkaroola and the Cowell Jade for starters. Also the Colebrook Hill mine has good specimens with axinite (eg. [www.mindat.org]). I will seem If I can photograph a couple but there must be good images about?
Ralph

Regards,
Ralph
avatar Re: Actinolite
April 01, 2009 01:31AM
    
Hi Rock,
You probably have nice examples of actinolite from Wenatchee Ridge, Lake Wenatchee, Chelan Co., Washington, but here is my self collected specimen from that area. It is 11.5 cm x 5.5 cm and the lath like crystals are up to 3 cm in length.



avatar Re: Actinolite
April 01, 2009 08:10AM
Ralph,
I have added the Colebrook Hill locality using the image you showed on the strength that you say there are better ones around and that we can probably get a picture on one sooner or later. Give me a description of the locality. It is listed as a mine. What kind of mine is it? Are the specimens of axinite collected underground or from the surface. What do the best specimens of actinolite from the locality look like? I have seen specimens dribbling out of the locality for years and it seems that if someone is willing to go there and work hard they can always seem to find something.

Linda, That is a nice specimen of actinolite although a bit over exposed. I bet if you brought it down to visit some time we could put it on our microabrasive tool and really make the actinolite crystals jump out and you would have a much better specimen and then it would probably be better than the one we have pictured for sure.

Rock Currier
Crystals not pistols.
avatar Re: Actinolite
April 01, 2009 09:59AM
This is a famous location for axinite-(Fe),and next to this, tremolite-actinolite is the most common gangue mineral to be found at the site. White to bright green tremolite-actinolite occurs as radiating aggregates ("suns"), fibrous mats (variety byssolite), pseudomorphs after diopside and ragged to fibrous crystals, up to 30 mm or so in length in this mine. Specimens of actinolite (with associated axinite) may range in size up to 30 by 60 cm and can be quite aesthetic, especially when there is a smattering of axinite on the actinolite, giving a contrast of the purple axinite against the green actinolite. Superb specimens of actinolite, associated with quartz, axinite and arsenopyrite, can still be found today at the Colebrook Mine, but are usually overlooked for axinite. Samples are usually etched from calcite.

The site is an abandoned underground copper mine, later open-cut, worked from about 1898 to 1917 in a number of lodes on the top of Colebrook Hill. It is now is a designated official fossicking area, and although permits are not required, collectors are advised to obtain information on rules, conditions, etc. before visiting the area. Access is largely steep, difficult and dangerous in parts, and it is not recommended for the unfit, and visitors should not attempt it alone. Not much significant has come from this old abandoned mine in recent years as the track has become impassable. On my last visit, we had to bash our way up the mountain through heavilly snake and leech infested swamp and rainforest (half the party did not make it). There is still a large dump with abundant low quality axinite and actinolite, but it really needs hard work and new exposures to produce good specimens.

Regards,
Ralph
avatar Re: Actinolite
April 01, 2009 05:19PM
    
Rock, I can do that. I will be down in July so I will plan on wrapping it up and tucking it into my suitcase. Still looking forward to the spray down with the hose. Ha ha

Linda Smith
Rock Mama and Boogie Boarding Grandma
avatar Re: Actinolite
July 09, 2010 07:19PM
This is still one of those non-standard "grandfathered" series which does not follow IMA rules about division according to site dominance, so we still have 3 members (tremolite, actinolite, ferroactinolite) in what really ought to be a 2-species series, divided by Mg-Fe site dominance. I suppose it will eventually become that way, but the argument for keeping the Mg-dominant half of the series still divided between tremolite and actinolite is that those names are so entrenched in the petrological literature that they should be left alone. That same argument did not stop the 6 plagioclase "species" from being consolidated into just 2, and I think the plagioclases were even more deeply entrenched in the petrological literature than actinolite-tremolite. We already have a note to this effect on the Actinolite page on Mindat. I personally don't make a distinction between these 2, because I don't want to have to change all my labels later.
[Alfredo Petrov 2010]

Rock Currier
Crystals not pistols.
avatar Re: Actinolite
July 12, 2010 12:53PM
The IMA worry about offending petrologists who happily still use unnapproved or discontinued terms like crossite, hypersthene, oligoclase, picroilmenite, ferritchromite etc., so I'm not sure it would make much difference. I don't really mind people using these names any more than any other variety or group names if it serves a useful purpose, as long as mineralogists can use sensible end-members for strict definitions.

Regards,
Ralph
Re: Actinolite
July 12, 2010 01:42PM
Just maybe suggest a mention at the beginning that actinolite is an amphibole-group mineral. Also, as long as you are including byssolite localities (where good specimens are found), suggest you also consider the French Creek Mines (PA), mostly specimens from there just have it as a mat of fibers that serves as a "backdrop" for other minerals like axinite and pyrite, but rarely some actual crystals are formed such as in photo 137929:

© 2010, JGW
Re: Actinolite
July 05, 2014 01:51AM
Here is a big solid piece about a foot and a half across. I am torn between selling it, chopping it up and making something with it.
avatar Re: Actinolite
July 06, 2014 08:58AM
Have you cut any similar material? Where is it from?

Rock Currier
Crystals not pistols.
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