The phrase "albeit unprecedented" is correct and usable in written English.
It can be used to introduce a contrasting idea or to acknowledge a situation that is unusual or without prior example.
Example: "The team faced significant challenges, albeit unprecedented, in completing the project on time."
Alternatives: "although unusual" or "even if unprecedented".
Tony Blair and Bill Clinton later pitched in with their support, by offering an unprecedented (albeit solicited) public endorsement of Mr Ahern for his role in the Northern Ireland peace process.
Albeit rare, this finding is not unprecedented.
The Scottish Football Supporters Club says that tickets have been available in unprecedented quantities, albeit at a price.
Though the death and destruction these acts caused were on the scale of war, the acts themselves were acts of terrorism, albeit on a wholly unprecedented level.
In the US, there are voices of dissension being heard with regards to Iran: On Capitol Hill, support for a diplomatic resolution is attracting unprecedented - albeit minority - support.
The steps Bush outlined in somewhat more (though still sketchy) detail will come mostly in the form of police work, albeit police work of an unprecedented intensity, breadth, urgency, and global scale.
A fair point: the MNR took part in the rise and rule of several dictatorships, including the first, and arguably worst, three years of General Banzer's.The general's supporters argue that his time, 1971-78, as military ruler brought much-needed stability and unprecedented economic growth (albeit unsustainable growth, being based on loans, American aid and high oil prices).
Its quasi-democratic political system of Golden Liberty, albeit limited to nobility, was mostly unprecedented in the history of Europe.
He acknowledges, albeit grudgingly, that economic growth "initially" provided unprecedented opportunities to extend--and enrich--human lives.
