supposed to be 75% of the ilvl minimum to see the affix is the end level requirement to use. which would make the ruby prefix ~lvl77, but it doesnt work out, idk why, someone else can go dig for why it doesnt apply to jewels
20ed, 6str, 9dex, 60ar, 10@res (rare), 15@res (magic), 8 life, 15 mana, 9 energy, 40 defense, 30 single resist, -15% req are all mods that can spawn on lvl 30 or less jewels. max & min, for a magic jewel you can get 8-15 dmg or 24 max, on a rare you can get 12-18 dmg. the rare is a combinatin of one each prefix and suffix both containing damage, there is a 4 min and 9 max prefix and a 8 min 9 max suffix that all work together to get the potential 12-18 damage jewel. the 15 max damage suffix is a magic only affix, which is why you cant get more than 18 max damage on any rare jewel, but is why you can get the 24 max lvl 30 jewels (9 max prefix, 15 max suffix) and 30 max lvl 50 jewels (15 max prefix & suffix)