Investigations into Aesthetic Properties of Selected Granites in South Western Nigeria as Dimension Stones

The visual and aesthetic features of dimension stones affect both their marketability and applications in the construction industry. Assessment or evaluation of the aesthetic features is done by using the colour, texture and grain size, flaws and irregularities. South western Nigeria falls within the basement complex of Nigeria with abundant granites of various colours. Despite this, little exploitation has been undertaken. This study is carried out to determine some granite rocks’ suitability for use as dimension stones. Dimension stones are classified in the International Smarket as single-coloured or multi-coloured. The colour is the major parameter that determines the price, besides other physical properties. Colour identification was done using the mineralogical composition and colour spectrum. Variation in colour was observed to be as a result of differences in the mineralogical composition of the granite rocks. Five of the granites investigated are single-coloured (Awo, Ewu, Supare and Ikere), while the Ore granites are multi-coloured and the texture of all the granites are either porhyritic or equi-granular. It was observed that none of the samples exhibits any form of microcrack. Scanining Electron Microscope (SEM) investigation shows that only the Awo granites have small percentage of sulphide mineral which restricted their use as external claddings.