If you have more than 1500 achievement points, today you would had unlocked the third achievement chest which comes with a choice of any Zenith weapon skin. Once you choose a particular skin to unlock, you will be able to acquire unlimited copies of that weapon skin from your acheivement panel in your hero tab. I chose the Zenith Reaver, an axe skin, since I am using dual axes on my warrior.
I really like the look of the Zenith weapons, they are among the prettiest looking skins in Guild Wars 2. For my next Zenith weapon skin unlock at the fifth achievement chest, I plan to choose the Zenith Spire, a staff skin, since my elementalist uses a staff.
Also, here is a picture of the Sun Catcher back armour skin I mentioned yesterday.