Baking to 202 with Pixie Powder Cinnesticks, Brewing to 248 with Minotaur Hero's Brew. You can take one over 200.
In classic the cap was 200, jewelcraft was the only tradeskill to go above 200 for a very long time, but it had humble beginnings and was originally designed not to go over 200. It originally scaled differently and had fewer possible gem combinations. Blue diamonds were only for quests and didn't combine, and most combinations made different things.
Here's a chart of the old combinations (bottom of page), trivials went 3 5 8 10 13 15 18 20, up to 200. 78 combines, two broken recipes, and a new trivial every 2.5 points, rounded up.
http://web.archive.org/web/200103310...ewel_table.asp