On a major project it is advisable to get a consultant on board early. In the selection of natural stone the following should be taken in consideration:
• The system must be best suited for the cladding of your project
• For entrances should be used materials that do not track.
• Wall finishes and vanity tops in bathrooms and toilets areas must be able to
   take the abrasives found in soap and perfumes.
• Use non slip finishes in wet areas 

The testing of natural stone is required when the material is being used in construction. The following tests are required in the EU.

• Natural Stone Masonry: EN 771-6, EN 1467
• Internal & External Cladding: EN1469,
• Code of practice for the design and installation of natural stone cladding and
   lining: BS 8298
• Paving, Setts and Kerbs: EN 1468, EN 1341, EN1342 EN 1343 
• Slate & Stone roofing: EN 12326-1
• Internal Flooring: EN 12058
• Modular Tiles – Internal Flooring, Cladding, Ceiling and Stairs: EN12057

There are many testing companies, however it is important that it is checked that the tests are also accepted abroad.