Start with a dark outline, color-wise start with a darkened version of the color and make your way up to full white in the middle for that glow effect, then use a non-solid brush (like the pencil tool) to half-erase the black lines on the interior of the crystal (or if you can’t change the brush type on the eraser tool, go over the black lines with a faint layer of white to make it less bold)
Idk I made this way up as I went, I legitimately have no clue what I’m doing. Do what feels right. Remember crystals are never formed symmetrical like they are shown on jewelry like rings and necklaces, they are jagged and and can pretty much be shaped however the heck you want, it’s your crystals
