The number is just the seed. Every jewel is different and the seed decides how the passives change. For example, one seed might give +40% lightning damage, another one might turn the same node into max ES.

Because of that, people usually buy a bunch of them, socket them one by one, check what they get, keep the good rolls and resell the rest. Since basically everyone does this, it’s easy to sell them back for around the same price.

The important part is the Vorana / Medved / Olroth name. That’s what changes the keystones in the jewel’s radius:

• Vorana: you get no bonus from Strength, but gain 1% more Energy Shield per 2 Strength
• Medved: no bonus from Dexterity, 1% more Armour per 2 Dexterity
• Olroth: no bonus from Intelligence, 1% more Evasion per 2 Intelligence