The following demonstrates a basic idea for socket-able weapons.

SocketableWeapons.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace SocketableWeapons
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            var random = new Random();

            var shortsword = new Weapon(2, "Iron Shortword")
            {
                Damage = 23
            };

            // 50% chance to drain mana
            shortsword.SocketedGems[0] = new Gem("Midnight Sapphire")
            {
                HitAction = delegate(Weapon self, Actor target)
                {
                    if (random.Next() % 2 == 0)
                    {
                        target.Mana -= 1;
                    }
                }
            };

            // 50% chace to deal an additional 50% damage
            shortsword.SocketedGems[1] = new Gem("Rage Ruby")
            {
                HitAction = delegate(Weapon self, Actor target)
                {
                    if (random.Next() % 2 == 0)
                    {
                        target.Health -= self.Damage / 2;
                    }
                }
            };

            var baddy = new Actor
            {
                Health = 100,
                Mana = 100,
                Name = "Badie"
            };

            shortsword.OnHit(baddy);

            Console.WriteLine(baddy);
            Console.ReadKey();
        }

        public class Actor
        {
            public string Name { get; set; }
            public int Health { get; set; }
            public int Mana { get; set; }

            /// <summary>
            /// Returns a <see cref="T:System.String"/> that represents the current <see cref="T:System.Object"/>.
            /// </summary>
            /// <returns>
            /// A <see cref="T:System.String"/> that represents the current <see cref="T:System.Object"/>.
            /// </returns>
            /// <filterpriority>2</filterpriority>
            public override string ToString()
            {
                return string.Format("Name: {0}, Health: {1}, Mana: {2}", Name, Health, Mana);
            }
        }

        public class Gem
        {
            public string Name { get; set; }

            public Gem(string name)
            {
                Name = name;
            }

            public WeaponAction HitAction { get; set; }
        }

        internal delegate void WeaponAction(Weapon self, Actor target);

        public class Weapon : Socketable
        {
            public string Name { get; set; }
            public int Damage { get; set; }

            public Weapon(int sockets, string name)
                : base(sockets)
            {
                Name = name;
            }

            public void OnHit(Actor target)
            {
                foreach (var socketedGem in SocketedGems)
                {
                    socketedGem.HitAction(this, target);
                }
            }
        }

        public class Socketable : IEnumerable<Gem>
        {
            public Socketable(int count)
            {
                _socketedGems = new Gem[count];
            }

            private readonly Gem[] _socketedGems;

            public Gem[] SocketedGems { get { return _socketedGems; } }

            public IEnumerator<Gem> GetEnumerator()
            {
                return ((IEnumerable<Gem>) SocketedGems).GetEnumerator();
            }

            System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
            {
                return GetEnumerator();
            }
        }
    }
}