Mask of Psychometry

The Mask of Psychometry was a Kanohi that allowed the user to view the past of an object by touching it. However, most were unable to control what part of the object's past they were taught and it could only be used on one object at a time. It couldn't be used on a living being to see their own history, but using it on a mask of theirs could do this.

History
Helryx, the first Toa in the Matoran Universe, wore a Great Mask of Psychometry making the Kanohi the first one to be worn by a Toa. This made it quite a famous mask for a short while.

Due to her heavy involvement in the Order of Mata Nui, an incredibly secretive organization, Helryx herself became obscure and her fame vanished almost entirely. As such Masks of Psychometry became rare masks due to the absence of the being who gave them their popularity. Many found their powers to be incredibly situational and useless in common situations, pushing them further obscurity. The only useful application that was found for them was for solving mysteries, and as such many of those who worked jobs involving stealth and espionage commonly wore these Kanohi. Because of this, the Kanohi then adopted a new association with those who hid and worked in the shadows, reigniting it's familiarity in the opposite direction to become an infamous sign of infiltration, treachery, backstabbing behavior and seclusion.

Despite this, the mask was still commonly used for those involved with espionage, resulting in those who used it themselves to obtain a bad reputation. Several movements were even made in morally bright communities to ban the mask because it "prompted suspicious behavior". Those against the movement to ban it regarded those who believed otherwise to be ignorant and unwilling to see the other, non-suspicious applications the mask had. After centuries of controversy many began to once again see the mask as more of a nuisance and it became obscure once more.

On the reformed Spherus Magna, Masks of Psychometry became very rare. It is thought that one sector of the movement against the Mask secretly seized and destroyed many Masks of Psychometry, although the reason in their current rarity is still mostly shrouded in mystery.

Great
In Destiny War, Helryx used her Great Mask of Psychometry on a piece of Rahkshi armor to try and trace it's origin.

Noble
In The Feral Plains, Turaga Maroona used her Noble Mask of Psychometry on Jeko's Matoran Kanohi to view his own recent history.

Great

 * Toa Helryx
 * Toa Maroona - Formerly; became Noble when she transformed into a Turaga

Matoran

 * Maroona - Formerly; became Great when she transformed into a Toa

Noble

 * Maroona