In terms of certified examples, the 1911 Quarter Eagles is the second most common date of the Proof Indian Head series (second only after the 1908). However, "common" is a relative term because any Matte Proof Indian Head Quarter Eagle is a rare item because their tiny mintages. The 1911 is a case in point - only 191 were made. In the early 1900s, few collectors could afford to purchase and hold gold coins. In addition, the matte finish proved to be unpopular with collectors who were already familiar with (and preferred) the brilliant and cameo Proofs the Mint made prior to 1908.
Top condiiton examples are elusive. The subtle, sandblast finish is easily marred, and any contact with another coin leaves a bright, shiny mark. Many have been dipped, or stripped, leaving them with a pale yellow color that is far removed from the rich, golden-green, original color. The finest example of which we are aware is a monster PCGS PR68+, nearly two full points ahead of the nearest competitor.