The price of the obsidian shield has fallen dramatically to near its high alchemy value. This made the Obsidian shield a good item to high alchemise, due to gaining profit out of it at times.
Before the Evolution of Combat, some players speculated that this was the equivalent of a dragon kiteshield at its time, having a 60 Defence requirement and being red with black spikes before the armour update.
In the 46th Postbag from the Hedge, TzHaar-Mej-Tak mentions that an obsidian shield is used in a similar way to a defender, rather than a shield. This explained its former strength bonus.
While wearing Warpriest of Zamorak armour, equipping the shield causes a brightness effect on the cap, causing it to appear much brighter than before, appearing charcoal grey instead of black.