The phrase "a unique icon" is correct and usable in written English.
It can be used to describe something that is one-of-a-kind or stands out significantly in a particular context, often in relation to culture, design, or branding.
Example: "The Eiffel Tower is a unique icon of Paris, attracting millions of visitors each year."
Alternatives: "a distinctive symbol" or "an unparalleled emblem."
Broken Sword offered a unique "conversation icon" system which would not reveal to the player what the protagonist was about to say; Cecil's intention was to make the game more cinematic.
A unique Profil.es icon can easily be added anywhere you can place HTML code, such as e-mails, blogs, and personal websites.
A unique Profil.es icon can easily be added to emails, blogs, websites and anywhere HTML code can be placed – including sites such as eBay, MySpace, Facebook and Match.com.
It's a huge watch, to be sure, and the renders/prototype models show a unique and colorful icon-based UI that might work better than the cramped black and white design of other devices.
According to Afsaneh Najmabadi, the lion and sun motif has had "a unique success" among icons for signifying the modern Iranian identity, in that the symbol is influenced by all significant historical cultures of Iran and brings together Zoroastrian, Shia, Jewish, Turkic and Iranian symbolism.
He has a unique ability to be an icon to teenage snow rats and widely recognized by grandmothers at the mall.
The London Eye is a unique attraction and a contemporary icon of London and the UK, so there can be no better way to get this important message across".
Flora Helvetica (Lauber and Wagner 2001) is an interactive guide to the flora of Switzerland that allows the user to search for an identification match with a multi-access key that utilizes icons in a unique way (Table 1: Best Practice 3).
They can provide a custom icon, screenshots and a unique description to distinguish their app.
