Montblanc celebrated its hundredth anniversary in 2006; the ceremony was held on 11 January 2006 at the Laeiszhalle in Hamburg. For the anniversary year the company issued a series of writing instruments carrying one unmistakable feature: in place of the usual white star in precious resin, the cap top holds a diamond designed and cut specially for Montblanc in the shape of the Montblanc star. The cut, with its 43 facets, was protected worldwide for the brand, and the stones were selected in the colour grade Top Wesselton.
The anniversary pieces spanned several price brackets, from very elaborate and correspondingly expensive editions to models within reach of collectors on a smaller budget. Nor did the star diamond remain confined to 2006: it went on to become the distinguishing feature of Montblanc's upmarket lines, where it likewise replaces the resin star in the cap top.
Placing a piece reliably therefore calls for the model designation, the numbering and the papers as well as the diamond, since the diamond star on its own is no proof that a pen belongs to the anniversary year.