Iceberg lettuce, also known as crisp head lettuce, is one of the most popular varieties of lettuce used in street food to fine dining cuisines the world over. This leafy green is a great source of fiber, iron, vitamin A and C, potassium, and calcium with very low calories. The iceberg lettuce head is spherical in shape resembling a small cabbage with 9 to 11-inch diameter. The crisp leaves on an iceberg lettuce head are tightly packed with high-water content. The lettuce leaves on the outside are green in color while leaves tend to be from pale yellow to white as you move closer to the center of the head. Iceberg lettuce is quite popular in cold wedge salads and lettuce wraps. The iceberg lettuce is a great source of potassium, iron, calcium, fiber and vitamins A, C, and K.