Hi Fernando
,
I also believe it is a spear butt. A spiked butt had a use for 'sticking' in the ground..... and 'if needs must' your enemy.
It is unlikely this was a counterweight for a throwing spear. Throwing spears by definition are lighter (in weight) to achieve greater distance.... usually iron is 'coiled' wrapped at the butt end if weight was required.
The type of spear with a spiked butt are usually the 'held' type and often used in battle like a wooden staff (quarter staff, 'Bo' the Japanese version etc) Obviously the bladed spearhead could be used to stab, but also was used to slash / cut when used in an arcing motion. The spiked butt was useful for defence from attacks from the rear or side.
The Masai, when facing a lion, have been reported as holding the spear, butt stuck into the ground as the lion leaps to attack. In this way the animal's weight provides the penetrative force...the butt prevents the spear from 'sliding'.
Shaka, modified the traditional spear by shortening the shaft and increasing the size of the bladed spearhead. Due to the 'regimented' tactics he employed ie lines of zulu's using shields to deflect attack and expose the assailant to a stabbing attack. (A very similar tactic used by the Romans .. ...however they used the gladius, the short stabbing sword which was well suited to this technique.)
Shaka negated the spear butt because (a) having 'lines' of men in rows meant that their 'backs' were protected and (b) with the 'row' in front stabbing the enemy there was a real danger of a spear butt injurying warriors in the 'row' behind ....ouch
Your example could be ceremonial, but am sure a spear butt nethertheless.
Kind Regards David