[Rockhounds] unusual question

[Paul]

In "unusual question," Dennis wrote,

 >must preface this question with the fact
 >that I have very little formal training in
 >chemistry and geology,

I am not an expert in mineralogy myself.
However, I suspect that if I am terribly wrong
in my answers, other members of this
list will let the both of us know in
uncertain terms.

 >but greatly enjoy the hobby of mineral
 >collecting on many levels.

The Fossil Forum also has a mineral section for
mineral collectors. However, it is only visible
to registered users. The Fossil forum is at:
http://www.thefossilforum.com/index.php?

 >Some time ago in generally discussing
 >minerals, and specifically zeolites, I came up
 >with one of "my" questions. Where did the
 >aluminum come from? I asked. The reply was
 >unusual but perhaps convincing. I was told
 >that aluminum is nearly "ubiquitous" or
 >everywhere.

The aluminum is "ubiquitous" as part of the
minerals that form rocks, typically volcanic
rocks, and natural glasses, primarily volcanic
ash. The aluminum is made available for the
formation of zeolites from these rocks and
natural glasses when they are either
dissolved or altered by alkaline ground,
formation, or marine waters.

 >I was wondering if Potassium falls into the
same category as "ubiquitous". I would think
 >you would need some eroded deeper seated
 >material to derive potassium.

Cations such as sodium, potassium,
magnesium, calcium, and barium can all
form zeolites. Potassium is not necessarily
needed to form zeolites if other of the above
zeolites are present. When present,
potassium typically can come from either
the alkaline water; altered volcanic rock or
glass; or some combination of the two.
sources.

 >Is there a metamorphic rock type that is
 >completely devoid of aluminum or potassium?

Rare quartzites can be quite pure and contain
only very small amounts of aluminum and
potassium. For example, high purity quartzites
can be found in Norway. For example.

Müller, A., Ihlen, P.M., Wanvik, J.E. and Flem,
B., 2007. High-purity quartz mineralisation
in kyanite quartzites, Norway. Mineralium
Deposita, 42(5), pp.523-535.
http://www.uvm.edu/~lewebb/TitaniQ/Pat/Analytical/Mueller%20et%20al%202007%20kyanite%20qtzt.pdf

Petrological and Chemical Characterisation of
High-Purity Quartz Deposits with Examples
from Norway. in J. Götze and R. Möckel, eds.,
pp. 71-118, Quartz: Deposits, Mineralogy
  and Analytics, Springer-Verlag, Berlin, Germany.
DOI: 10.1007/978-3-642-22161-3_4
https://www.researchgate.net/publication/258049498_Petrological_and_Chemical_Characterisation_of_High-Purity_Quartz_Deposits_with_Examples_from_Norway

Although they are high purity, they are
still not "completely devoid" of aluminum and
other

 >If in the case of stellerite, if there was NO
 >aluminum present to form stellerite what
 >would it form?

It would not form.

 >Or is there vacant space where the
 >aluminum would fit?

No.

 >In the case of erionite, is it possible to be
 >missing potassium and still construct
 >the same mineral??

There are Erionite-Ca and Erionite-Na.
as seen in “Erionite Series” at
http://www.iza-online.org/natural/Datasheets/Erionite/erionite.htm

Although potassium is not the dominant
cation in Erionite-Ca and Erionite-Na, the
some potassium needs to be present for
it to be erionite.

Yours,

Paul H.