There’s always been doubt regarding deciding if granite is properly sealed or not. Most people don’t know how a sealer works, and with so many opinions flying around, it can be difficult to know what to do.
A couple simple tests, that you can do yourself at home, will help you determine what kind of stone you have, if it’ll be problematic, how to clean and care for it, and most importantly, if sealing your countertop is necessary.
Determining Your Stone Type
Here’s the test you can do at home to learn a lot about your granite. The lemon Juice and Oil Test will tell you how absorbent your stone is, as well as what type of stone you have. It could be a silicate-based stone (granite) or a calcite-based stone (marble, travertine or limestone), or possibly a mix of both.
Why is this so important? It will help you choose the best stone for your home and / or help determine the characteristics of stone you already own.
Granite is the stone of choice for use in the kitchen or bathroom, where all kinds of substances will come into contact with the countertop. Some granite is more absorbent than others, while other granite is actually mixed with calcite, which will cause the surface to corrode or “etch” when exposed to acids – such as lemon juice, coffee, alcohol, salad dressing, etc.
Etching has nothing to do with sealing granite countertops. Sealing will not prevent etching or scratching. Etching is a chemical reaction between the acid and the calcite that physically alters the stone, which is especially noticeable on polished surfaces.
All marble, travertine and limestone will etch and most are also prone to staining, which is why these stones are typically not recommended in the kitchen. This is unless you are willing to let them age naturally, spots and all.
Some stone is very dense and won’t absorb a thing, or stain at all, especially when polished. This helps decrease absorption rates for any stone.
For a countertop that won’t etch or stain, you’ll want granite. To determine if your stone is granite, perform the lemon juice and oil test in the kitchen, wet bar, bathroom or anywhere else where lots of lotions and liquids could be a problem.
NOTE: Perform this test on a sample of stone that you are considering buying before installation. Otherwise, perform the test in a small, inconspicuous area.
The Lemon Juice and Oil Test
- (Only if applicable) Line up all your samples in a row.
- Drip enough lemon juice to form a dime-sized puddle on the first sample.
- Do the same with vegetable oil / olive oil.
- Observe the surface of the stone through the puddles and note the time.
- If you see the stone darken right away, this stone is very absorbent and shouldn’t be used in the kitchen.
- If it takes 4-5 minutes, this stone simply needs sealant and it will be applicable in the kitchen.
- If it takes 10-15 minutes to darken, a sealer should still be applied. But make sure it absorbs well and doesn’t dry on top.
- If the stone never darkens or takes more than 30 minutes, you have a near stain-proof winner that probably doesn’t need sealer.
- Wipe the sample clean and look at the spot where the lemon juice was. Is it dull compared to the shiny polish on the rest of the sample, or did you notice the lemon juice fizzing / bubbling on the surface? If so, it contains calcite and shouldn’t be used in the kitchen.
- Perform the same test for all your samples.