This paper reports on the usage of excavated sedimentary rocks from Jurong Rock Caverns in Singapore as a precursor to produce geopolymers.The rocks were transformed to powder form in a sequence of steps including the use of hammer, jaw crusher and ball miller.The rock powder was characterized using X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and particle size analyzer.XRD results indicate that the rock powder is highly crystalline while the elemental composition found from EDX shows high amounts of silicon and aluminum in the rock powder.The extent of dissolution of silicon and aluminum ions originating from the rock powder in alkaline solution was measured using inductively coupled plasma optical emission spectrometry (ICP-OES) and was found out to be very small.This indicates that if the rock powder is not used in combination with an active geopolymer precursor such as metakaolin, it would be a very weak geopolymeric precursor.Further, a number of geopolymer test specimens were prepared by addition of different amounts of rock powder to metakaolin and mixing them together with the sodium silicate solution.The compressive strengths of the hardened specimens were tested.Experimental results indicate that though the rock by itself cannot participate much in the geopolymerization reaction but it can very well act as a filler and high compressive strengths can be attained by keeping the Si/Al ratio of the geopolymer mix close to 2.0.