Benefit of Jewels
In early game (first arc) socketing jewels is skippable. I say that because you will level up fairly quickly and change gear regularly. Celestia/Zafaria on is when you will want to consider which gear you might be keeping for a while. The gear that is socketable is going to be your athame, amulet, ring, deck and very rarely a wand. The deck is the only one (prior to Krysalis/Darkmoor) which is interchangeable based on which jewel socket it offers since they don't have an additional stat earlier on. For example, you might be a level 60 wizard who really needs accuracy but all the decks at that level only have square or tear sockets. Going down to a lower level deck for a triangle socket so that you can add accuracy is the right call. You will have a smaller deck but appreciate the sacrifice when you don't fizzle so much.
Schools of Jewels
When you click on a jewel in your backpack you can preview what the jewel looks like. The color of the jewel should be a dead giveaway since they are the same colors that are assigned to each school. In addition, the names for these colors are the same names we have seen with those reagents that correspond to the different schools. Here is the list anyways:
Amethyst - Storm
Ruby - Fire
Sapphire - Ice
Citrine - Balance
Jade - Life
Onyx - Death
Peridot - Myth
Hematite - Shadow
Types of Jewels
Circle (Offense): This includes, damage, critical, pierce and outgoing heals. Keep in mind the damage is a flat rate damage rather than a percent like you would see on your gear. For this reason, critical is a better bargain than damage.
Square (Defense): This includes resist, block, stun block and incoming heals. Again, resist is a flat rate not a percentage, although out of the choices for square sockets it is usually your best option.
Triangle: This includes power pip percent, shadow pip, accuracy and item cards. Both power pips and accuracy are extremely valuable because they help you to hit faster and consistently. Depending on your school and gear choices, you might not need any jewels to get your power pips to 100% and in that case the choice is an easy one. For everyone else, (in late game) it is good to prioritize pips, get your total to 100% and then use the remaining triangle sockets for accuracy. I am not a believer in using triangles for cards with the one exception being the Morganthe cards, mostly because they are 4 pip aoe and not all schools have that available, namely Life and Death.
Tear: This includes health, mana, energy and fishing luck percentage. As far as your everyday questing/farming gear, this is a no-brainer. If you have an athame and a ring that have energy on them you might want to use energy or fishing luck for those but for everything else, use health.
Star: Jewels specifically for pets. In effect, it is as if you are adding an additional trait to your pet. If you add it early in the pet's life, this will prohibit your pet from learning that trait since they cannot have 2 of the same trait. I feel it is best to wait to see what the pet learns naturally, then use the jewel to supplement what your pet did not learn.
Quality of Jewels
The quality is based on the wizard's level not the gear level. You will not be able to socket a jewel that is higher than your current level.
Level 15 - Cracked Jewels
Level 25 - Chipped Jewels
Level 35 - Flawed Jewels
Level 45 - Blemished Jewels
Level 55 - Dull Jewels
Level 65 - Plain Jewels
Level 75 - Opaque Jewels
Level 85 - Clear Jewels
Level 95 - Polished Jewels
Level 105 - Lustrous Jewels
Level 115 - Shiny Jewels
Level 125 - Sparkling Jewels
Crafting Jewels
The first thing to keep in mind in crafting jewels: it is a gamble. There are no universal jewel recipes so forget about getting pain giver or universal resist this way. The recipes for the different jewels can be bought by your local crafting recipe NPC. Each recipe will be the school and the level range. So if your level 35 Death wizard needs some jewels you would get the recipe for Death level 35-55 jewels. You may get level 35, 45 or 55. You may get death block, death crit or death pierce, et al.
Recipes:
Level 15
Level 15-25
Level 15-35
Level 25-45
Level 35-55
Level 45-65
Level 55-75
Level 65-85
Level 75-95
Level 85-105
Level 95-115
Usually it is wise to have your highest wizard craft jewels for your lower wizards, unless you have a friend who can taxi you to worlds you haven't unlocked yet in order to buy the recipes. The recipes in each world have a starting level lower than the average level for that world and since the level is random it would be better to get random higher rather than random lower.
* Star jewel (pet jewels) recipes are sold in the Pet Pavilion. As far as the jewel recipes go, they are considered completely separate than the other recipes sold in each world. There are no wizard level limitations on the pet jewels however there are pet age limitations.
Plants, Packs and Farming, Oh my!
The jewel plants (5 different plants that harvest one of each of the jewel types) I have found to be at times lucrative. I do not recommend any of the jewel packs to get jewels. It is far too random and your chances of getting all level 15 is too high. However, the Rockhammer's Jewel Pack is the way to get the jewel plant seeds, which is what I did. I started with one seed of 2 of the 5 types of plants and I have 87 plants now at least 10 of each type. Each type of seed will randomly harvest one of the other type's seed in addition to it's own. While universal resist is not included with these plants, pain giver, proof, defy and other types of universals are. Universal resist jewels are only bought with tickets or farmed. The sparkling universal resist is going to be with the end game bosses, extremely rare drops.
Socketing Wrenches
Some jewel sockets need to be unlocked in order to socket jewels and are a one time use. To unlock them, you can either spend crowns (of course) which is on a sliding scale according to the level of the gear or you can use a socketing wrench. There are 6 different wrenches currently in the game. As the level of the equipment goes up, the wrench required may change. Keep in mind, it does not matter what level your character is, just the level of the equipment.
Level 15-34 - Novice Wrench
Level 35-54 - Adept Wrench
Level 55-74 - Expert Wrench
Level 75-94 - Master Wrench
Level 95-114 - Artesian Wrench
Level 115-130 - Grandmaster Wrench (barring any changes made within the Karamelle/Level 140 update)
Keep in mind:
* You cannot socket jewels to anything you cannot currently wear, whether it is a higher level gear or another school's gear.
* You cannot transfer an item with jewels on it in the shared bank. You will have to remove (destroy) the jewel in order to share the item you have previously socketed jewels on.
* You can share jewels in the shared bank.
* There are a few jewels (usually from the $20 W101 gift cards) that come with a special jewel that will not be broken when removed. Other than those few, all other jewels will be destroyed when removed.
* In addition to saving very good universal gear to pass down to your lower wizards, you may want to do the same with jewels you come across as you are questing/farming.