It is certainly possible to add lava rock and ember material around the base of the log set to add realism, as long as it does not impede the flame in any way. Common accessories to use are the Real Fyre Lava-Fyre Granules - LF-10
and the Real Fyre Ember Glow - EM-1
. As mentioned, the embers can be used near the flames, but should not come in to direct contact with them. You may check with a local Golden Blount dealer to see if the missing log can be procured to complete the set.