If you have me, I‘m inside your head, If I‘m a bad one, I might cause you to be dead, OP had to have me to be able to post this riddle, I have an even number of letters, so there‘s no single letter in the middle. What am I?

I sparkle bright in gold or blue, a precious gem, but not brand new. Found in rings and royal flair, What stone am I, with regal air?

Spin me around and watch me glide, On a peak where dreams reside. A small word, but it stands tall, Often the target of ambition's call.

I'm best pals with salt, If you sneeze, it's probably my fault. I can also be green, yellow or red. Or so spicy your taste buds will be dead. What am I?

Add an s to my end, and I’m an OG cartoon character from the Stone Age. Add a sandy destination to my end, instead, and I become a world-famous golf course in the Golden State. If I’m trapped inside your shoe, I’m endlessly annoying. Flat versions of me are perfect for skipping across water. By definition, I measure somewhere between four and sixty-four millimeters in size. What am I?