The influence of nano-silica and zircon additions on the sintering and mechanical properties of in situ formed forsterite fired at 1550°C for 2h was investigated. The results indicated that, nano-silica improved in situ formed forsterite at the firing temperature, while zircon additions enhanced the sintering of the investigated samples. XRD analysis and SEM examination observed a good crystallinity of in situ formed forsterite with nano-silica and/or zircon additions. Densification parameter (BD ∼3.22g/cm 3 and AP ∼5.82%), cold crushing strength (CCS ∼285MPa) and micro-hardness (Hv ∼660) were enhanced with zircon additions.