It's foraged using the forage skill. If you don't have a forage skill, try the going to the bazaar zone and using the /baz command to search for some in there. It might be sold in Abysmal Sea or Crescent Reach, but didn't look like it from the item page you linked.
Ctrl+M - Skills tab, check the buttons. If not there, right click one of them to see the list possible choices. If it's not in the list, then you can't forage (at least without buying the AA to raise the skill to 50). Only Iksars, Wood Elves, Rangers, and Druids can forage by default, if I remember correctly. If you can forage, it shouldn't take more than a few successful tries in the guild lobby to get one.
You don't search either. Just hit the forage button when in any zone. Guild lobby has the fewest choices so more likely to get one there.
EDIT 2: Not buyable from a merchant in unlimited quantities. Can vendor dive, which is searching merchants for a limited quantity of items players have sold to them. Buying from other players that can forage is probably the best and fastest way to go. Check the aforementioned /baz command in the bazaar zone, or ask /ooc or in /general channel.
Another longer option, is to create a Wood Elf or Iksar race 1st level character, since they start with 50 Forage skill and use that character to try and forage one in the guild lobby or even gloomingdeep mines tutorial zone and use the shared bank.
Yther Ore.
Edited, Dec 31st 2013 5:47pm by Yther
Edited, Dec 31st 2013 6:10pm by Yther