all 20 of the Crystal affixes are the same as the Epic affixes they are based on (except for MP & HP on Hit, which are only 2x Epic affix values) except they are 3x values. you can only have one Crystal affix on an Item, but not on Pets or Trinkets.
practice using Epic affixes so you have an idea of how to use Crystal affixes later.
example: Epic Attack Speed +15% vs. Crystal Attack Speed +45%. Attack speed cap is +60%. consider how this can affect your build!
I got these values from the DQ Wiki, and I believe these values are currently correct. I hope this helps.
don’t use Quartz at all to take a Crystal affix off of an Item. it’s better to have at least 5 Obsidian and hope for the best. it’ll be less frustrating than using Quartz.
when Crafting an Item, it’s better to work on getting the Crystal affix you want first and then put the Mythic affix on after. I’ve done it the other way and it really sucks if you get a Crystal affix you don’t want on your Build. especially when you are low on Crystal & Mythstones