Though the occurrence of diamonds and their prospecting indicator minerals in the Dajingtou area of western Shandong Province has long been known, no substantial breakthrough has been made in the exploration of the diamond primary ore. Based on the study of crystal morphology and chemical composition of the indicator minerals, this paper compares the characteristics of indicator minerals in natural heavy sand and in the Dajingtou volcanic rock to reach the following conclusions. Firstly, the Dajingtou area has both diamond indicator minerals and diamond- bearing rock indicator minerals and is a favorable area for diamond mineralization in the western Shandong region. Secondly, the type and proportion of indicator minerals in the Quaternary are consistent with that in the Dajingtou volcanic rock. We propose that the indicator minerals are supplied by the Dajingtou volcanic rock, which contains a large proportion of indicator minerals of the eclogite, such as G4- pyropes, omphacite. Thus, it can be concluded that that the Dajingtou volcanic rock is lamproite that passed through the edge of diamond producing area and carried the characteristic minerals. According to the characteristics of the lamproite’s cluster distribution, the Dajingtou area and its surroundings are potentially high- quality target areas for the new type of diamond prospecting. Future prospecting efforts should be focussed on the primary diamond ore of the lamproite type.