Application of quasi-elastic properties in geotechnical site characterisation is a subject matter addressed in this paper. Recent developments in field and laboratory techniques in geotechnical site characterisation are reviewed. Problems and counter-measures in characterising in-situ geomaterial properties are discussed, including an examination of the performance of soft clay sampling practices worldwide. The inter-links between reconstituted (i.e., non-aged) and natural (i.e., aged) soil, between soils and soft rocks, between stiffness at small strains and strength at large strains, and between field (i.e., mass) and laboratory (i.e., element) testing are discussed. Important topics that are highlighted include: in-situ "structure" of natural sedimentary clays, mechanism of ageing (i.e., the transient behaviour from soils to soft rocks in the process of diagenesis), disturbance of laboratory samples, and estimating engineering properties "in the ground" for geotechnical design.