The caption explains that it is a 1mm grid.

An excellent suggestion. How can Mindat get IMA to sit up and take action?

The axinites from the New Melones Dam spillway show strong violet to pale brown pleochroism but were determined to be axinite-(Fe).

Probably the bolt was immersed in copper-bearing water somewhere around the smelter. an electolytic reaction ewould then start dpositing copper on the steel (iron) bolt. It could have in been buried in porous soil with copper bearing solutions percolating through.

The play of color could be due to fractures in the material.

There many glaucophane schist  occurrences, mostly metagreywackes in the Franciscan rocks of the Santa Rosa area. These rocks look like glaucophane bearing metasediments.

The prismatic crystals look like quartz included with a dark mineral, possibly your 'ferroactinolite'.

The way to remember the difference between stalactites and stalagmites is the mnemonic "the mites go up and the tites come down" . I suspect both are just varieties of calcite but could be called limestone variety dripstone.

we would still need the source references

Possibly iowaite. John Glidden, mine geologist at Palabora,  had quite a number of pieces that looked very similar.

Glaucophane quartz schist with pyrite, from a Franciscan 'knocker'

Another 'Rockcurrierism'  "they are all my children, and all my children are beautiful".

Thanks, Keith. I'll give it try.  I don't really my want all my bad pictures up there for public view.

I'm giving the My Catalogue feature on Mindat a trial run. So far so good but I have run into a couple of issues.  1) Is there a way I could import an Xcel or Access database into My Catalogue?  This would avoid a rather tedious one-by-one entry process. 2) I notice when adding a photo it ...

Agree with Harold, banded iron formation chert. 

I posted this photo in error.

I take that back looks more like Julcani mine arsenopyrite needles.

Arsenopyrite crystals from Raura look like this.

What analytical tool generated the spectrum? 

HCL will not tell you much, I believe.  Optical mineralogy or PXRD on crushed material will be the way to go. Don't know if many people are competent in optical mineralogy these days but many  universities have XRD equipment.

So not a manganese oxide or hydroxide. Mottramite seems a good guess at this point.

The Republic of the Congo dioptase occurrences are frequently associated with and occur in a manganese-rich friable, poor consolidated rock locally known as 'terre noir' or black earth, often interpreted as karst-fill. Nodules of pyr olusite are often found in this rock and in the laterite soil ...

A small scratch on an actinolite or even a riebeckite specimen will not produce a hazard that will cause any kind health hazard. Asbestosis is cause by continued insult to the lung tissue not by one time exposure of miniscule amounts of fibers,  That being said I believe I see 120 degree ...

This is a fine grained sedimentary rock with unknown components.  the weathering surface suggests a a carbonate but not guaranteed. The high bulk SG suggests either a dense carbonate (siderite?) or sulfate (celestine, baryte?). You're going to have resort to a thin section, or bulk chemistry, ...

STRUCTURAL DYNAMICS OF SALT SYSTEMSMartin P. A. Jackson, Bruno C. Vendeville, Daniel D. Schultz-ElaAnnual Review of Earth and Planetary Sciences 1994 22:1, 93-117   

I believe that evaporites or their past presence and the role of slat tectonics are often under-recognized in field mapping.  evaporites are often fugitive, either leaving their depositional site by solution or diapirism or both but they do leave traces, such as cherty, pebble conglomerates ...

This looks like an oxidized marlstone to me, i.e. a carbonate rich siltstone. The red-pink color due to oxidation of iron-bearing detrital clasts.

Interestingly, the libethenite crystals from Nkana occur in ovoid cavities in a grey arenite rimmed by albite and quartz which again may be after anhydrite nodules.

There's a wealth of relatively new data on the Copperbelt sedimentology, basin formation and structure. The earliest reference to evaporites and anhydrite nodules that I know of is Annels, 1974.   Theron, 1974 is a fairly good synopsis as are the papers by Murray Hitzman and his students ...

I agree with Richard Gunter, the replacement/open space filling is probably after gypsum or anhydrite. The Copperbelt sediments are part of an evaporite sequence and nodules of anhydrite/gypsum often replaced by albite quartz talc assemblages are ubiquitous.

Borax, kurnakovite, colemanite, etc .i.e. most hydrous borate minerals alter in air. It is usually stated the alteration mineral is tincalconite. However, Richard C. Erd (USGS mineralogist at Menlo Park, CA) identified "formates" in the alteration coatings of borax. He was unsure if this was ...

I believe the label reads PCapt Ian Treweck. Maybe rank and name of collector/collection?

I believe your 'fusion' crust is a hydration rind that forms on the nodule as it interacts with meteoric water,  The rind being of a different composition from the interior can also have different mechanical properties and spall off. 

The location issues may be due to several fundamental map making issues. Most importantly the geodetic datum used on the paper map on which the locality is plotted. In Australia, mapping mismatches of 200 metres are common and result from difference between the old Datums (AGD66 ⁄ ...

Looks very much like a pyroxenite, i.e. a rock made up of >50% pyroxene group minerals, in this case looks like close to 100%. certainly an ultramafic rock. Erick Vercammen may be right that it is enstatite but not easy to tell with out a thin section or XRD identification.

It looks like serpentine with veins of chrysotile.

It seems they were issued in 1937 and the original company has probably merged with or been taken over by other companies. Or it went out of business. Most small mining companies suffer this fate, You could check the registry of corporations in the state the stock certificate was issued,

I visited Isle de Los several times in the mid-2000s to check out the syenite outcrops for serandite, aegirine, etc., etc.  It's a very pleasant day's outing by boat from Conakry. You can go by regular ferry or contract a local boatman to take you out to the island  where there are ...

Ilmenite is usually black. Is the tan coating possibly an alteration to anatase/brookite Fascinating piece by the way.

Hard to say. They may detrital cobbles, or colluvial material or in situ in weathered host rock. What else was in the trench and how were the blocks related to the other material?

Are you sure its all garnet. To me it looks like the surface is intergrown with something like amphibole or epidote.

Thank you

It is not an agate. It looks like a silicified, fine-grained volcanic airfall ash.  The initial volcanic components are laid down in layers and later silicified during compaction and diagenesis. The resulting rock was then fractured tectonically and the fractures infilled with a new generation ...

I agree with Ed, a piece of black chert, possibly part of an iron formation that has has been fractured and infilled by later silica rich material.

Somehow I inadvertently added a photo of a completely different specimen to the two  images of this specimen, Can Mindat move the last image and  text to a new  Min-ID entry?

Thanks, Harold. I'll do that. There's a couple of others that have the same issue. By the way Rock collected this with Bob Bartsch in 1980.

https://www.mindat.org/photo-303966.html is the same specimen as https://www.mindat.org/photo-650485.html. Suggest it be made a child of TC7-3VC 

The colors seem quite unrealistic. Is there a way to correct the color balance. If not I suggest the image be removed from the public gallery.

Looks like a volcanic glass nodule, i.e. obsidian

It's quartz stained red by iron oxides. The only way you'll be able to tell if it's gold bearing is to assay a sample or crush a 1-2 kg sample and pan it. The second way won't necessarily be conclusive and the first will only tell you the gold content of that sample.   You will have to ...