Describe an object that brings you luck or that you carry for good luck

I wouldn't say that I'm a very superstitious person, but I do have one lucky object: a small blue stone that my mother gave me before my university entrance exam. It's smooth and round, about the size of a large coin, and it has a tiny white line through the middle.

She found it years ago on a river bank during a family picnic, and she kept it in her purse for a long time. On the morning of my exam, she put it in my hand and told me that it would help me stay calm. I was extremely nervous, and I didn't really believe it would work, but I put it in my pocket anyway. During the exam, I kept my hand on it whenever I felt anxious about a question, and somehow, I managed to concentrate. A few weeks later, I received good results and got a place at my first-choice university. Since then, I've taken the stone with me to every important event, such as exams, interviews and presentations. It stays in my left pocket or in my bag.

I think of it as lucky mainly because of that first success, though I understand that the real reason was my preparation and not the stone. Perhaps it's a psychological effect. When I hold it, I remember my mother's confidence in me, and that boosts my own confidence. In that sense, it does bring me luck. Even if it's only in my mind, I don't see any harm in it, and I will probably carry it for many years to come.