There’s a very common symbol in Turkey called the Evil Eye. The Evil Eye originates in Egypt, as Osiris' eye, and I’m not sure how long it has been popular in Turkey. Made of various sizes, materials, and colors (though most commonly pocket size, glass, and blue), it has become a cultural (non-religious) symbol here in Turkey to protect against the evil eye of jealousy.
The above picture is from another personal blog; it has a good explanation as well.
It is used as a well-wish and protection for new endeavors: businesses, vehicles, marriages, etc.
A tree adorned with Evil Eyes that people have hung, possibly to protect their nearby businesses.
A shop which sells many different types of Evil Eyes.
Here’s a great post on someone else’s personal blog about the Evil Eye:
And here’s the lengthly, multi-culture version from Wikipedia: