I just read this, from Anne graham Lotz.

I first heard her in South Africa and I get her devotional everyday.   Interesting enough, the irritation of ones lose of job is major in our lives.  I cannot know what type of pearl God made of my irritation, but I hope, I have learned how to pray and trust  Him as Sovereign and He can take care of all our needs, small or large, if we only lay them on the alter and allow Him to work His way.

The twelve gates were twelve pearls, each gate made of a single pearl.

Revelation 21:21, NIV

Pearls are formed when a small grain of sand becomes embedded in an oyster, irritating it. To soften the irritation, the oyster coats the grain of sand with a smooth layer of what is called mother of pearl. As long as the oyster can feel the irritation, it continues to coat the sand with layers of pearl. What kind of irritation would have been necessary to form the pearls that make up the gates to our heavenly city when they are so large they can fit into a wall that is two hundred feet thick?! It must have been more than just irritation. It must have been horrendous, severe suffering!

I wonder . . . are the pearls a reminder, every time you and I enter My Father's House, that we enter only because of the intense suffering and death of God's Son? Do those pearly gates reflect the Cross of Jesus Christ?