There are so many variations in gravel that you can easily find one to fit in with your existing garden. I am not overly aware of which colors I use in my garden. I don't have a section of blue flowers, a section of white flowers, a section of red flower and so on. So I chose a creamy white colored gravel that works with all the colors in my garden. The gravel has a shiny look, especially at night when the lights are on and reflecting off the rocks.
While I chose to go with a single color and type of gravel, I have seen some wonderful landscapes using several types and colors of gravel combined with stones and rocks. The possibilities are endless.