Buying a new house is exciting. However, a lot of homes come with surprises not revealed during the walk-through. An example would be a toilet that floods the floor every time you flush. Another is thinking that you have granite countertops, when they might not be granite at all. Here is how you can test your countertops to see if they really are granite, and then decide what to do from there.
Scratch the Granite Lip
If your countertops really are granite, you do not want to damage the visible surfaces. If the counters have "lips," (i.e., edges that jut outward from the countertops and/or curl under) this is where you will want to do the tests. Get under there with a nail and scratch. What should happen is a very fine scratch that causes stone film to drop. The scratch may be very hard to see until you apply water.
"Paint" the Scratch with Water
Using a simple paintbrush, brush water over the scratch you just made. If the material is granite, the scratch will momentarily become darker and more visible. It will be less noticeable in seconds, when the water evaporates.
Geologic Acid Test
If you still are not sure what kind of countertop material you have, buy a geologic acid testing kit. This kit will not hurt your countertops unless you spill the acid all over the tops and leave it there. On the underside of the counter, where you scratched the stone, apply a couple drops of this acid. Do not worry, it will not eat holes in anything. It is not that type of acid.
You may want to put paper towels down on your floor under the testing area. If the acid does not bubble or fizz, you have either granite or dolomitic limestone. Other geologic tests involving what you see and feel will help determine which of these two types of stone may be your countertops.
Granite Countertop Services
If you absolutely have to know beyond a shadow of a doubt that you have granite, call a granite countertop service. The contractor can come take a look at your countertops and tell you right away exactly what you have. If you bought the house and paid more than you should because you thought you were getting granite countertops when you got limestone instead, you can either keep what you have or ask the granite countertop contractor to replace the countertops.