Petrographical properties: structure, chemistry, mineral

Extraction of stone Stone is usually obtained from open quarries, with only some types of marble, slate and limestone being obtained from underground mines. When exploring new sources, the extent of the deposit and the properties of the stone are estimated by way of ultrasound measurements, or samples are obtained from deep boreholes. Hydraulic wedges are driven between the blocks along natural cleavage planes in order to separate the blocks. Diamond-beaded steel wires and cross-cutters (sort of oversized chainsaws) have also become common in recent years. The aim of quarrying is to obtain aproximately right-angled blocks of a suitable size and in doing so to generate as little "waste" as possible. Quarrying involves destruction of the landscape, and creates large quantities of dust and debris. New deposits may therefore only be quarried when certain official stipulations are met. Those stipulations include restoration of the landscape once the workable deposits have been exhausted.
Cleaving of the stone is usually carried out directly in the quarry especially in the case of paving stones and stone for ashlar walling. Otherwise, the stone is transported to factories for further processing - it is then that we speak of dressed stone. The use of regional deposits and hence short distances between quarry and works considerably improves the life cycle assessment for natural stone. Various methods are used to process the quarried blocks:
Steel-shot abrasion or diamond saws:for 20-80 mm thick slabs (the time taken to saw through a 1.20 m high block of granite is about 1-2 days)
Taglia Siocci saws:for stone tiles or long strips with a thickness of about 15 mm
Gangsaws with circular blades or steel wires: for the production of coarse slabs> 80 mm thick; steel wires can also create three-dimensional workpieces.
Application of stone in buldings Stone in the form of aggregates for concrete and mortar or for producing mineral binders accounts for the largest share of natural stone in building. In order to establish the suitability of a type of stone for building work, the stone industry classifies stones as hard (igneous and some metamorphic rocks) or soft (sedimentary rocks). However, owing to the availability of relatively "soft" igneous rocks and very hard sedimentary rocks, the specific physical properties (compressive strength, frost resistance, abrasion resistance) should always be checked for the application when choosing a type of stone. Generally, stone is suitable for the following applications in building:
Masonry
Gabion walls
Facade cladding
Floor finishes
Internal linings
Roof coverings
GABIONS Gabions are wire cages filled with crushed rocks or recycled concrete rubble. They are frequently used in civil engineering applications as retaining walls, and are simply stacked to the required height either vertically or to an appropriate incline. Compressive loads are transmitted through the stones or concrete rubble, and any spreading movement is restrained by the tensile forces within the wire cage. Normally, the cages are of heavy gauge woven or wweellddeedd sstteeeell mmeeshsh,, wwhhiicchh mmaayy bbee zziinncc,, aluminum/zinc alloy, or PVC coated, but for use in load-bearing building applications, such as walls, stainless steel should be used. Gabions are now being used as significant components in building construction, where the particular rugged aesthetic is required. Gabions may be delivered on site filled or flat packed for filling and fastening, usually with a helical binder in alloy-coated or stainless steel. A range of sizes is available based mainly on a meter module.