Granite Tile Adhesive... Instead of Mortar. Does it exist? I've had granite slabs professionally installed contained by my kitchen in the...

I've had granite slabs professionally installed contained by my kitchen in the recent past. I saw that they didn't use mortar, instead, I saw them use some sort of adhesive that come out of a tube gun.

Ideally, I'd like to use something close to that instead of mortal to install 12x12 granite tiles? What would you recommend?Please keep surrounded by mind that these are going on an outdoor bbq island.

Lowes told me to stick to mortar, and that adhesive/caulking won't work. They said that it will ghost through. But I don't see anything close to that on my existing granite slab which was installed 2 years ago.

When I asked the store where on earth I bought the granite tile from, they said that I could use Caulking with silicone to grip the granite tile to hardibacker.

So which is it?

Thanks in finance....
What liberal of paint would you use to...
Answers:    Pc has the right opinion the sheer weight of "slab" granite allows different adhesion requirements from tiles. Also the certainty that it is outdoors is a factor here. If you really want this done right there is a compromise... Hydroment make a product called "Ultraset" it comes within a premixed sausage tube (but it is NOT CHEAP) it is THE BEST product to adhere these within an outdoor application, it acts terrifically much like thinset but have a much higher elasticity. This is the ONLY product I would recommend for this installation.
Best room ever!!?
Save yourself abundantly of time and trouble and just use the thinset mortar. Especially since the installation is outside.