I hold your thoughts in chalky white, erase me gently, and I’m blank as night. A thousand lessons may pass through, yet each swipe lets me start anew.

I can sometimes be cracked, and you can usually find me in a trail. If I describe your mind, your thoughts are probably off the rail.

Little specs floating in the air, settling on all your stuff. It'll never be truly gone, no matter how much you wipe and buff.

In pantry jars my kind resides, A pinch of me can change the tides. I bring warmth and flavor in a trice, With sugar and me, I make everything nice.

The first you need for your house or your car. The second can cause damage when thrown from afar. Combined it allows an arch to stand tall without cement or tar. Metaphorically it is the part of a system that is the brightest star.