Therefore, it is imperative to select the right quarry depending on the required use. We recommend the book EL MARÉS, written by Ramón Sánchez-Cuenca, which describes the stone characteristics (density, porosity, strength, colour, etc.) of the 20 active quarries in Majorca. Formentera quarries are already exhausted.

In this project we will use 1st quality stone from quarry Cas Busso and the characteristics are:

-Appearance & colour: Whitish colour, compact, dense, no grain, very hard.
-Apparently Density: 2.1 g/cm³.
-Open porosity: 45.6 %.
-Compressive strength: 557-627Kg/cm².
-Impact resistance: 100- 120cm.
-Capillary Absorption: 4.1%.
-Resistance to crystallization: >17 cycles.

The use of sandstone has the following advantages:
1. It needs no surface treatment. Not even revoke, plaster, paint, or repellent.
2. It needs no maintenance. It will improve over time with the emergence of the patina.
3. It is a perspirable material that regulates humidity.
4. It has an 80% reduction in CO₂ emissions compared with a facade of two sheets of concrete block, with exterior covering and interior plaster.

In terms of social sustainability, it maintains or recovers the trades and building traditions of the islands. We remind that is possible to build barrel vaults and arches at economic prices.

The extraction of stone does not produces damage on the territory, unlike what happens with the aggregates extraction. Actually, the resulting quarries spaces become very interesting places which may allow many uses.