Soldiers are melee/ranged fighters, who focus on offense or defense. Soldiers use strength as their main stat. They party with other classes and provoke enemies to form a mob of monsters for higher and faster exp gain. Soldiers use one-handed or two-handed swords, blunt weapons, spears, axes, and shields. Their second job form is either Knight or Champion.
Knights
are the defensive branch of Soldiers. Knights usually use one-handed weapons and
shields and lure large groups of enemies and excel at defeating single enemies,
"bosses," relying on their high defense to do it safely.
Champions
are the offensive branch of Soldiers. Champions usually use two-handed weapons
such as axes, spears and two-handed swords. Champions excel at destroying many
enemies at once, and the axe branch of skills is the one best trained in PvP.
The spear and two-handed sword skill branches use strong area of effect (AoE)
skills to kill multiple enemies at once.
The most important stats for soldier is Strength. It adds attack power, defense, max hp and weight. So the gems most suitable for soldier job is Ruby cause it adds strength.