Can you be harmed by staring at induction stove cook top

We have recently remodelled our kitchen and moved from a gas hob to an induction hob. In general it cooks much the same as gas and you get similar levels of control over the temperature. One style of cooking that is not recommended is 'slide' cooking as this will likely scratch your hob surface - this can be mitigated by putting a piece of parchment paper under the pan or lifting the pan off the hob. we don't use a wok and can't see how we could with our hob.

The surface of the hob gets hot but not as hot as it would it it were gas or electric this means that spilt / spattered food doesn't generally burn on to the hob surface and it is much easier to clean.

The hob is touch control and so far we've not had any problems with this. If you lift a pan off the heating zone it will switch itself off automagically after a certain amount of time. Before this happens if you put a pan back on the zone it carries on cooking. If there are no pans on any active zones then the whole thing switches off after 2 minutes.

We chose a NEFF Flushline hob that sits in a natural black granite work surface and the whole thing is positively beautiful and a pleasure to work with.

I have an induction stove and have had similar marks. I think rumtscho is right; these are mineral deposits from water. Water gets between the surface and the pan, most likely because the base of the pan was initially wet (spillage from the pan will mostly end up beside it, and only areas directly under the pan will get significantly hot), the heat of the pan evaporates the water, leaving dry deposits.

There is some good advice on cleaning glass stovetops from eHow, which suggests leaving a "[vinegar-drenched] paper towel on the stove top for an hour", and using ceramic cooktop cleaner if still present.

But I've found these marks can be mostly prevented by making sure the base of your pan is completely dry before putting it on the stove.