I top your pizza and your martini, In salads and dips you’ll find me. From my pit comes liquid shine, Tiny, round, and so divine. Who could I be?

I tighten when things get loose, and loosen when things get tight.

In kitchens of old It kept things quite cold Think of it as a teaser For an appliance like a freezer

I have a heart that’s full of heat, Yet no blood flows through my beat. I breathe in iron, hum and groan, To warm your skin and guard your home. I drink hot water, steam, or oil, To keep the freezing cold at coil.

This five letter word for a sparkle can sometimes be seen in someone's eye, but you might also say that someone's glasses do this, or maybe metal. It can be associated with low or flickering light.