Wakefulness is very important in vajrayana, or the tantric teachings. It is indestructible, like a diamond. Once you are a diamond, you are strong and invincible, and because you are self-contained, you are ready to work for others. This diamond also has loving kindness and a sense of humor, which shine right through. If you look at a diamond early in the morning, it shines, and if you look at it in the middle of the night it still shines. A diamond is always glowing and glittering.
From The Tantric Path of Indestructible Wakefulness, Volume Three of The Profound Treasury of the Ocean of Dharma, by Chögyam Trungpa, pages 59–60