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main source of pore-fluids circulated through the pores and voids presented in
the lime mortar plaster studied were composed of CO3, Cl, and SO4
bearing meteoric water 1-3.  The circulating meteoric water is
composed of a mixture of underground water, rain water and estuarine water. The
water is bicarbonate enriched relative to carbonate ions. The solubility of Ca
(HCO3)2, increase with increasing temperature. When
aqueous pore fluids containing the calcium (Ca2+), bicarbonate (HCO3?),
and carbonate (CO32?) ions, together with dissolved (CO2),
the relative concentrations of these carbon-containing species depend on the
pH; bicarbonate predominates within the range 6.36-10.25 in water.  Increasing of bicarbonate ions induces
crystallization of hydrated minerals during the course of depletion of CO2
content / pressure or exhaustion of dissolved CO2 or increasing of
pH values. Physical and chemical characteristics of natural water depend on
several factors of the geological strata in which groundwater is flowing (i.e.
the aquifer), time of residence of water in the stratum aquifer, and
environmental conditions. Generally ground water is enriched with bicarbonates
rather than carbonates within terrestrial environment 24.  The deposition SO4 minerals were
controlled by presence of CO3 and Cl constituents 25.  These constituents appear to be contaminated
with SO4 tetrahedrons in the structural formula of sulphate bearing
minerals. Similarly, Si, Al, Fe+3, Mg, Na, K ions enter as
impurities present in the sulphate minerals to accommodate SO4
tetrahedrons and tabular crystals of gypsum on horizontal bedding planes.  There are pairs of adjacent layers parallel
to (010) which contain Ca ions and tetrahedral SO4 ions. Between
successive pairs of layers, the water molecules are located as in the
structures of zeolites 5 and 20. The negative reliefs of these minerals
indicate that they have lower refractive indices than Canada Balsam (R.I.
1.54). Developments of expansion cracks are useful identification marks for
these minerals.

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