If you go to Draynor Village and ask the Wise Old Man whether you should keep the blurite sword or not, he will say that it is "fairly nice" and "a decent weapon", but will also comment that you don't really need it and it would only be special to Sir Vyvin himself. He will then offer to buy it for six coins.
Since it does not have a fuller, the Blurite sword would be considered a Type XVII on the Oakeshott Typology scale. [Arguably closer to an XV.]
The Blurite Sword resembles the old design of the Decorative Swords from Castle Wars.
Due to a hidden update, the stance of the Blurite Sword whilst being wielded has been changed to a regular swords' stance.
Prior to the Evolution of Combat, the accuracy of the blurite sword was the same as a steel longsword, but with only the strength of an iron longsword.
Prior to 18 May2015's update, the Blurite sword could only be obtained during the quest. Previously, there was no way to obtain it after, so some players decided to take two blurite ore and four iron bars to Thurgo to make a copy for themselves. This update also added an offhand version. Because blurite bars are members only items, free players will still need to use this method to get any duplicates.
Even though two iron bars are needed for Thurgo to make the sword in The Knight's Sword quest, when players smith it themselves nothing but a single blurite bar is needed for the entire sword.
There appears to be a blurite sword on some of the desks at the Grand Exchange.