Colour intensifier for natural granite

[ringi]

We are planning on using StonneFlair by Bradstone from simplypaving as their price is very good and we don’t live in London. Most of the paving will be Silver Gray Granite with highlights in Natural Granite.
We like the look of natural granite paving better when it’s wet as it goes a deeper “black� so contracts with the Silver Gray granite better. So I am looking at colour intensifiers to use on the Natural Granite before laying it, what should I expect from them over the long term?
The other option would be to buy a better “black granite�, however as we will only need a few m^2 of it, delivery cost become an issue – we live in Stockport, I would also want it in a thickness of 25mm for ease of laying.

[London Stone Paving]

Not really sure what you mean by natural granite. I had a look at the simply paving website and they seem to have two colours on there, the silver grey and the mid grey. Not that many companies supply black granite because its very expensive. You will get a decent colour contrast from the silver grey and the mid grey without sealing