Answer:
Used on a diamond and left on a board. It's great for a gymnast his grip to restore. What is it?
Looks like water, but it's heat. Sits on sand, lays on concrete. A play on the eyes, but it's all lies.
You can see nothing else, When you look in my face, I will look you in the eye, And I will never lie.
My first is an insect; my second is a border; my whole puts the face in a tuneful disorder.
Upon me you can tread, though softly under cover. And I will take you places, that you have yet to discover. I'm high, and I'm low, though flat in the middle. And though a joy to the children, adults think of me little.
If it’s information you seek, come and see me. If it’s pairs of letters you need, I have consecutively three. What am I?