LOL! It doesn't match anything, so it doesn't contrast with anything either

Sound thinking. I'm with stoopid
Here is a plan of action I was going to take to add flourite to my tank, so it might work with yours if you want to add the different gravel badly enough:
(a) Rinse the
snot out of the new gravel. I mean put it in the rinse cycle five times and then soak it with a firehose after powerwashing at the carwash after a three week soaking in a 20 gallon tub.
(b) Get a clear plastic tube around 3" in diameter and about 2 feet long and a scoop that is more narrow than the tube opening.
(c) Hold the clear tube vertically on the existing gravel bed and pour the new gravel (is it rinsed thoroughly?) with the scoop into the tube until you have about 2 - 3" of gravel standing in the tube.
(d) Gently and slowly lift the tube until the desired thickness of gravel is deposited on the old gravel bed. Carefully move the tube around the deposit area until the tube is empty of the new gravel.
Cover only half the tank bottom surface as you don't want to overwhelm the nitrite and ammonia eating abilities of the remaining old gravel. Cover one more quarter in two weeks and cover the remaining portion two weeks after that. If my bio-reasoning is unsound, please correct me.