A well-known canted antiferromagnetic Fe3BO6 with functionalized properties is an important material useful for light energy carrier, electrodes, gas sensors, and biological probes. In this investigation, a facile synthesis is explored in order to obtain Fe3BO6 of small crystallites in a specific shape of nanoplates by self-combustion method. To access (i) whether Fe3BO6 is formed at the as-prepared stage and (ii) how it stands stable with a residual carbon surface layer, thermal gravimetric (TG) analysis has been carried out by heating 10-20 mg powder (as-prepared) at a typical 10 K/min heating rate over 300-1100 K under air or argon atmosphere. The electronic absorption, infrared (IR) and Raman spectra studied for the Fe3BO6 sample in this investigation elucidate how the density of states of the phonons and valence electrons confine in small crystallites. IR and Raman bands in the oxygen polygons also confer the results of forming Fe3BO6 with a bonded surface carbon layer. A stable bonded surface layer supports thermal stability of small crystallites and it affects other useful functional properties.