Gel pens are similar to rollerball pens, but rather than liquid ink, they use gel based ink. Gel ink is thick, and when on paper will be much more vibrant, and it will also not blend away into the paper, this means that on dark paper, light colours will show up, and the ink can also hold shimmery material or glitter.
Gel pens have their place in everyday writing, due to the boldness of the black ink, and the way the colour stands out on the paper, and they also have a place within art, and colouring, due to the super bright colours, the glittery finishes and their ability to write on lots of different materials.