what's with the hourglass?

When I click on one, I hear like a timer ticking, and then it stops. Is the hourglass
supposed to represent something?

If I am not mistaken, it slows down the other teams (pauses timer).

Hourglass adds minutes to your time......at least that's what the explanation said during the intro.

I didn't pay enough attention at the beginning so I missed the explanation. They should have a little link to a "rules" or "about" section and let you know about the gems, hidden items etc.