I had posted this page on my old blog in January, but it disappeared. Here it is again:
To create gorgeously dazzling Gems you most likely will need a white ink opaque pen to draw highlights and speckles. Even if you're not creating gemstones, at one point you will want to use a white pen over tan or black paper. I was testing the different pens I recently got, here is the summary of what I found.
My favorite for Gems, by far, is the white Sharpie paint pen (water based, not oil), which lays very smoothly over the waxy Prismacolor colored pencils. Although at first the tip doesn't look that thin, it's very easy to produce even the tiniest dots with it.
My second favorite pen is the Uni-ball Signo Broad, excellent to work directly over paper. It doesn't perform as well over waxy colored pencils, though.
My last recommendation is the Molotow, an acrylic paint pen, which although has a very fat nib, is very opaque. The only drawback is the price!
Here is the full testing and analysis of the white pens I own:
Keep in mind that these recommendations are mostly geared towards COLORING GEMS, which requires very opaque white coverage. In some cases, you will WANT to have more translucent and watery effects.
To view my other shading supply recommendations, visit this page: Shading Supplies