Bringing a stone to Compostela

[Robert E. Spenger]

The chemist in me demands that I respond to this. Chemically, limestone and
seashells, as well as marble, chalk, coral, and calcite are all the same, but
are just different physical forms. At high temperature (i.e. in a kiln or oven)
all of them break down to lime, which is used to make concrete and cement. The
ground up material would break down more quickly and require less fuel. For
that reason it would be more convenient to use seashells or chalk than the
others because it would be easier to grind them up.

This reminds me that I saw a number of fields in Galicia, and northern Portugal
as well, that had a light sprinkling of broken seashells on them. My inner
chemist commented that the local farmers must have decided that their soil
needs a dose of calcium.

Sorry about the lecture. I can't make that inner chemist keep his mouth shut.

Kathy Gower wrote:

> I have actually read something similar, but having to do with bringing the
> scallop shells back, to be ground as lime, to be used as mortar in the
>                 Templar Church at Rosslyn in Scotland and also a church in
> Portgual, I believe. It wasn't the stone that was significant, but rather
> the scallop
>                 shells which the pilgrims brought back....
>