The word on playa dust and links for the newbie -

[^Rhino!]

I'm going to dispel a lot of rumors and stuff with this post about playa dust. More than a few people, including a few professionals, have tried to wrap their brains around the problem, and though (in my opinion) some are close, nobody gets the idea. By trade and training, I've been a successful sedimentary geologist deciphering such phenomena dealing with rock and soil for the last 20 years so I'll give you my best take on the situation, one which I think is reasonable and factual.

The subject has been brought up both here on tribe and on eplaya. Links provided here for the Burningman tribe:

[url]bm.tribe.net/thread/e41a...b60cf1946671[/url]

and

[url]bm.tribe.net/thread/4ef5...f904d755e768[/url]

A fairly detailed discussion is here:

[url]www.sacredexotic.com/blog/20...813.html[/url]

All harken back to this link here:

[url]www.foresight.org/Conferenc.../Gillett1/[/url]

(See table 2, sect. 6.1 about halfway down the page.

There is a link to a graduate student colloquium at Penn State here:

[url]www.geosc.psu.edu/GradCollo...ct2010.pdf[/url]

And I found one link about 'playa lung' here:

[url]eplaya.burningman.org/viewtopic.php[/url]

Based upon all of this information and the surrounding geologic information that's there, I've come up with my own interesting conclusions regarding the playa's dust.

Here's the whole story.

From the looks of the chemical analysis and the mineralogical data, the major contributors to the composition of playa dust are quartz, feldspars, and micas. Mj in the mineralogic analysis means 'major', and mn means 'minor'.

Reproduced here is the mineralogic analyusis (semiquantitative):

quartz - Mj
feldspars - Mj
Micas - Mj
non-silicate minerals - mn

IF you do your homework and use the chemical analysis numbers, you figure out that the silica (SiO2) has to be paired with alumina (Al2O3) in both the feldspars and the micas. The Fe2O3, MnO, and MgO go in the micas, probably of a muscovite composition.Part of the calcium oxide (CaO) and all of the soda (Na2O) go with the feldspars, probably anorthite and albite plagioclase compositions, but more towards the anorthite end. Diphosphorus pentoxide goes in apatite, a common igneous accessory mineral and detrital in this case.
Titanium dioxide is probably rutile or anatase, also common igneous accessories. The reason for the high LOI (loss on ignition) figure is the presence of water in gypsum (calcium sulfate dihydrate). How much? The correlative figure needed for the calculations is the presence of SULFUR, not listed in the analysis. But it makes sense, because in Empire you have the largest gypsum producing operation in the continental US.

SO, what you have is a mixed suite of minerals from the nearby Selenite and Granite ranges, consisting largely of granitic detritus. No calcium carbonate (calcite) there, or very little. You'd have to have the CO2 numbers to know for sure.

Here's a summary of all the preceding threads to date discussed on eplaya and Tribe, with my comments in parentheses:
• The playa is abrasive because of aluminosilicates. (I say true)
• The playa is corrosive because of carbonates. (Nope. carbonates are non-corrosive. Try sulfates....gypsum. Gypsum dried becomes anhydrite, and will suck the water right out of your skin)
• The caustic carbonates dissolve greases, such as lipids in the skin. (true for sulfates, not carbonates)
• The minerals are highly abrasive, ones often included in sandpaper and machining tools. (I say true)
Human results from dissolved lipids and abrasion: (all probably true)
• Playa foot
• Miracle wart removal
• Microderm abrasion for softer skin
• Degradation of hair (this was a guess based on what on person read on Wikipedia about shampoo and conditioner)
Other interesting facts:
• Playa can be added to molten glass. (true)
• Playa is good for cement mixing. (up to a point. As a drying agent, or pozzolan as it's known)
• Playa + vinegar = science fair project! (might be interesting...active ingredient in vinegar would be acetic acid)
• Spraying a large quantity of micro-fine mist of vinegar into a sandstorm would either be really cool, really smelly, and/or dangerous? (slightly dangerous, but not fatal. definitely smelly.)
• HCL, hydrochloric acid (aka Muriatic Acid), can be used in VERY diluted amounts as a less smelly alternative to vinegar, but do not use on skin! Look for cement and other industrial cleaning solutions for muriatic acid. (Don't even use the muriatic acid as a cement cleaner...it's still too concentrated and will burn skin)
Notes for the newbie: (I can agree with most of these...they won't hurt)
• Bring vinegar, lemon juice, or some other low-strength skin-safe acid.
• Definitely bring mask and goggles.
• Plan to never go barefoot, even if naked, unless you wash your feet off multiple times a day. Playafoot = BAD.
• Do not bring anything of value or sentimental, unless it will be protected from corrosion or washable with vinegar.
• If renting a vehicle, wash with vinegar or lemon juice, before returning.

Any questions?
Comments?

[curiousgnate]

So why does vinegar/lemon juice help while on the playa? I find just washing my feet with water does just fine. I have always wondered it it really does help more then plain old water, or if this is just myth, or very minimal help.

[Bob]

Rhino, while you're lazily cross-posting, please consider enabling BBCode in your profile if you want your URLs to work as intended.

[theCryptofishist]

So why does vinegar/lemon juice help while on the playa?

The acidity of the vinegar counteracts the alkaline of the dust. Chem 101.
And some people are less sensitive than others, I'm guessing you're the first kind.

[Bob]

I use vinegar on my hands after working with concrete, but never on the playa. All I've used on the playa is water for washing, quickly followed by Neutrogena hand cream, which is good for about two weeks in my experience, before I get cracks on my hands, face, asshole, etc.

[Sham]

I am just livening up the links here. I am too tired to have an opinion on this right now. I didn't try the links, just made them work!

EDIT: After trying to do a public service here, it appears that these links lead to dead ends. Sorry!

http://www.bm.tribe.net/thread/e41a...b60cf1946671
http://www.bm.tribe.net/thread/4ef5...f904d755e768
A fairly detailed discussion is here:
http://www.sacredexotic.com/blog/20...813.html
All harken back to this link here:
http://www.foresight.org/Conferenc.../Gillett1/
(See table 2, sect. 6.1 about halfway down the page.
There is a link to a graduate student colloquium at Penn State here:
http://www.geosc.psu.edu/GradCollo...ct2010.pdf
And I found one link about 'playa lung' here:
http://www.eplaya.burningman.org/viewtopic.php

[curiousgnate]

Just wondering what rhinos thoughts were. is there really that much alkalie (sp?) that vinegar actually makes a difference.

[Bob]

Rhino did not explain that he was cross-posting a response he made to someone on tribe.net who reported a severe reaction to some as-yet-unidentified thing at Burning Man last year.

[Ugly Dougly]

Lots of big sexy words. I'm confused.

[^Rhino!]

Cross-posting, that I am.

It's some things people need, Bob. I apologize if it offends your sensibilities. If you consider it lazy, so be it. I just won't tell you about the two hours I spent calculating the molecular normins and doing a process called a CIPW normative to recombine the oxides in artificial minerals.

But that only works for PART of the molecular stew in the analysis reported by Gillett. With a 25.4% loss on ignition(LOI) figure (as you so correctly pointed out in Tribe, there's some other constituents not reported, like sulfur (in the LOI figure as SO3) and carbon (CO2 - which again would be in the LOI figure)as well as water (again in the LOI).

Calcium sulfate, not carbonate as previously inferred by some.Still alkaline as hell, though not on the same level as sodium hydroxide (lye).

It also EXPLAINS why there can be no direct contact with fire on the playa. It would heat up the gypsum to form calcium sulfate (no dihydrate because the water would be driven off.) You get anhydrite like that, which is plaster of paris. Add water again, it hardens.

And then, when material erodes around it in the future, you get a pillar of gypsum that's sticking above the playa that's as hard as concrete. Same thing happens in White Sands Nat'l. Park in the Tularosa Basin of New Mexico.

Just thought some might be interested.

[curiousgnate]

rhino can you answer my question?

[gyre]

So why does vinegar/lemon juice help while on the playa?

The acidity of the vinegar counteracts the alkaline of the dust. Chem 101.
And some people are less sensitive than others, I'm guessing you're the first kind.

But I'm not neutralizing a bomb, just trying to wash the stuff off.
I use ivory soap and water.

[Fire_Moose]

pour some vinegar on the playa and it will start to bubble and fizz. It's GOTTA do something!

[^Rhino!]

The bubbling and fizzing is from aragonite/calcite (both are calcium carbonate) crystals in the playa dust.

Vinegar works because it breaks the loose (covalent) molecular bonds between the playa dust and your skin oils. Simple as that. And when you consider that most vinegar is more water than acetic acid, it stands to reason that the gypsum gets rehydrated and washed off, too.

More questions?

[Bob]

Did you try enabling BBCode in your profile?

[^Rhino!]

Yes, Bob, I did. That's how it will be from here on out. Thanks.

[Bob]

Let us know when you have x-ray diffraction data on the clay mineralogy.

[Boijoy]

I got a slight rash on my thighs one year right after my evening " basin wash with soap & water". I think it was from scrubbing the playa in...
Hurt like a bitch for about an hour.. then it was gone. go figure.

[Bob]

Cooler water?

[Boijoy]

Cooler water?

possibly. I think that after a few days of applying things like suntan lotion, baby wipes, moisturizer, camp soap & playa dust, a quick sponge bath isn't "cutting it". I had a REAL shower the next day & it was wonderful!

[Ugly Dougly]

...Diphosphorus pentoxide goes in apatite, a common igneous accessory mineral and detrital in this case. Titanium dioxide is probably rutile or anatase, also common igneous accessories....

Whoo-doggie, Rhino! Them is purty words! You use your mouth purtier than a three-dollar French whore! I'm all wet over here.

[dragonpilot]

...Diphosphorus pentoxide goes in apatite, a common igneous accessory mineral and detrital in this case. Titanium dioxide is probably rutile or anatase, also common igneous accessories....

Whoo-doggie, Rhino! Them is purty words! You use your mouth purtier than a three-dollar French whore! I'm all wet over here.

Dougly...I'm not coming to meet 'n greet if you keep talking like that!

[EmilyD]

^Rhino, thanks for your explanations and rumor dispellations (?word?) I was just told this weekend that I should silicone coat any wires/electrical connections that may be exposed on our trailer. A friend took his artcar which has mechanical butterfly wings and although he thought he had cleaned all the playa dust off the wires, when it rained the invisible dust began a corrosion process. He had to replace the entire electrical system. So...do you think silicone will form enough of a protective barrier? Thanks.

[Snow]

I'd be interested in XRD data of playa, is someone working on this?

I also need to perform an experiment to see if playa can be substituted for salt in my ice cream bike to make ice cream as I ride around. I fear it would require far too much and just make a hell of a mess.

Hi Rhino!

[^Rhino!]

Unfinished business.

Bob wanted the links put in properly.

Here's the link to the current discussion on Tribe:

http://bm.tribe.net/thread/88266e9d-81a ... c9b87f8c3e

Previous discussions on Tribe:

http://bm.tribe.net/thread/e41af0ad-2bb ... 0cf1946671

http://bm.tribe.net/thread/4ef5347b-43b ... 04d755e768

A fairly detailed post by Ora Uzel:

http://www.sacredexotic.com/blog/2009/20090813.html

All of the above harkening back to the link here:

http://www.foresight.org/Conferences/MN ... /Gillett1/

This is from the 42nd annual Graduate Student Colloquium at Penn State:

http://www.geosc.psu.edu/GradColloquia/ ... ct2010.pdf

Gillett's paper does have a semiquantitative mineralogic analysis that looks like this:

quartz - Mj
feldspars - Mj
Micas - Mj
non-silicate minerals - mn

Mj meaning major component, mn meaning minor component. I've seen the exact same thing that was done for my office just recently for shales, using XRD, or X-ray diffraction. The problem with that is you actually need three separate runs to determine the clay mineralogy, if in fact there is any, and you're going to have to separate the materials from each other because the quartz peaks on the diffractogram overrun everything else. Normally some lab technician operating the diffractometer plugs names into the computer based upon what he 'thinks' or is told is there, and then the computer measures the peaks and spits out the results, both in a semiquantitative form and with reproductions of the diffractograms for the individual components superimposed on the main.

To do it RIGHT, you have to have three samples as I previously stated...one for an oven-dry condition, one which has been saturated and then redried, and then one which has been saturated with ethylene glycol, which gives the necessary readings to differentiate whether you're dealing with a 1:1 clay mineral like in the illite group, or a 2:1 clay mineral like in the smectite group. And if you're dealing with mixed-layer clays, then you need more samples to differentiate the components.

Also, Bob, think a minute there. Clays are phyllosilicates (sheet, or layered silicates), just like micas. Separating the two is a royal bitch and a half to make any reasonable determination from the type of the diffractogram that they got.

The problem of differentiating the individual clay minerals (if indeed there are any) in playa dust is worthy of at least a Masters' thesis. I separated all the components in the analysis and then used normative chemistry to figure out what was there based on the geology of the area. Quartz? Absolutely, with a source of the Granite Range. Same for the feldspars and mica. And then it STARTS to get tricky. I did find out one thing though, that there's probably a magnesium sulfate septahydrate out there. Geologists call it 'epsomite'. You know it as epsom salts. And it stands to reason because you're in an evaporitic basin, or you wouldn't have gypsum there. But still, I call that a tentative conclusion and not final.

I haven't had the chance yet to put a slide of playa dust under a polarized light 'scope yet, but believe me, I will.

Now, Emily D:

Yes to the silicone. and make sure you give wiring a generous coat. The first time I went to the playa I started having corrosion problems on the battery of my truck. That was solved using the little anti-corrosive felt rings you can get at an auto parts store for under a couple of dollars.


My research into the dust continues. Fascinating stuff.

[Bob]

That's funny, x-ray diffraction of clay and clay-like minerals was routine when I was an undergrad.

[^Rhino!]

Consider this, Bob.....I'm not associated with an academic institution anymore. I have to send out such things, and the analysis costs $$ I don't have at the moment.

Maybe later.

[gyre]

Sometimes epa or osha or someone else with a lab will run these for you.
But someone must have already done this, if they can be found...

[EmilyD]

Yes to the silicone. and make sure you give wiring a generous coat. The first time I went to the playa I started having corrosion problems on the battery of my truck. That was solved using the little anti-corrosive felt rings you can get at an auto parts store for under a couple of dollars.


My research into the dust continues. Fascinating stuff.

Thanks ^Rhino...I'll check out those felt rings. All in all we'll have 4 batteries and we don't want them corroding. There's a tiny little semi-exposed wire couplet that holds our trailer fuse. If that fucks up we're screwed. It will be coated liberally.

[Bob]

Please, let's not confuse the "newbies" any further.