Is it okay to use a Cast Iron Skillet on a Glass Stovetop?

Unless you want to do permanent damage to your glass stove top. Get rid of the cast iron skillet. That is a lot cheaper than replacing a stove top.

I wouldn't use cast iron on glass.

One thing that's important to note about what skillets CAN be used is they need to have a smooth bottom. Some skillets have ridges or a ring groove on the bottom surface and these can damage/crack the glass cook top. It's not that the ridges are scratching the glass but they cause excessive heat build up between the skillet and the glass.

the issue with cast iron skillets is that the method used to make cast iron skillets is a process

called "Sand casting".

where this becomes a problem for glass cooktops is that there is always

some imbedded sand that remains in the iron and it is this embedded sand

that is the issue.

this combined with the weight of the iron cookware, with sand imbedded In the bottom

will often cause a deep scratch in a glass cooktop

I personally really don't like the idea of scratching a big piece of tempered glass that

gets glowing hot in use...

I have a kitchenaid glass cooktop

It will be too heavy, also because it retains heat so well, it could cause the glass to explode.

No it will scratch the cook top.