Personally I think glass isn't very usefull in Cell materials,
unless you're thinking of actually heating it to melting point
and making a vitreous material, then it might be used in the mix...
And in my opinion Calcite is not a very good material for making Cells,
or at least not as far as I have been able to establish experimentally.
I have tried to mix in conductive and semiconductive powders with
calcite/gypsum type mixes in attempts to increase whatever output
they might yield, and in attempts to add dopant for increased polarisation
of the bulk material, but none of those experiments produced anything
above simple gypsum drying polarisation (the potential of which was extremely
low and disappeared when the stuff dried completely, except for one cell where
it seemed to continue but that was later found to have extensive corrosion
on the metal particles which proved the additional potential was galvanic).
But of course this is only intended as constructive info and you should by all means
do the experiments you have planned involving Calcite. You might just strike a
material composition that does produce higher and lasting potentials.
Low cost materials to experiment with you say? Well, it does sort of depend on
what style of Cell you're going for...
If you're going for a Hutchison-style Cell, the materials stated by John are pretty
clear and not very expensive at all: crushed pyrites, crushed galena, if you have it
crushed germanium (from Ge diodes for example), and Rochelle Salt as a binder.
If you're going for a more Reid-style Cell, the exact materials are vague but it certainly
is a sort of ceramic-like material which solidifies permanently. So if you're going for that,
you may want to look at fairly simple ceramic materials. I have used and still do use
things like Kaolin in Cell experiments, for example. (That's a type of white clay used in
pocelain for example)
Things like pyrites, galena, tourmaline, etc can often be bought at or via local mineral/
rock/crystal shops, or ordered online. Tourmaline can be expensive depending on what
colour you want (the green variety is much more sensitive to deep infrared than the black
variety for example, but also more rare and more expensive, usually), but "fools gold" pyrites
are relatively cheap and so is galena. Things like quartz (powder or sand), mica, kaolin,
plaster of paris, etc, can usually be bought at (or ordered at) a local ceramic crafts/potters supply shop,
or at arts&crafts shops, and are often not very expensive.
Several art supply shops in the region here also sell all kinds of powders intended as pigments
for painters to use in their homemade paint, and among these powders are potentially usefull things
like powdered copper, aluminium, silver, gold, iron, carbon, and various oxides.
Rochelle Salt and many other materials can be bought from lab supply shops but they can sometimes
be expensive. You can make it yourself too, from "Cream of Tartar", by a fairly simple chemical reaction
as some here have posted in the past. For that you will need some simple chemicals that can often be
bought at local supply shops. Quite a few materials can be made at home using such simple household
chemicals, if you know what you're doing. And the needed chemicals like caustic soda, hydrochloric acid,
etc, can most often be bought locally and cheaply.
And of course you can collect rocks of (or with patches of) the less common mineral types to get
materials. I'd go for the ones with patches of shiny, glittery, and preferably iridescent minerals on them.
And those with some metallic glitter or glare to them. But hey, that's me
