Mandalas are spiritual and ritual symbols in Hinduism and Buddhism that represent the universe.
The mandala is decorated with traditional iconography that includes geometric shapes and a multitude of ancient spiritual symbols.
Historically, the mandala was not created with natural, dyed sand, but granules of crushed colored stone.
Sometimes this included precious and semi-precious gems.
So, lapis lazuli would be used for the blues, rubies for the reds, and so forth.
Then they get down to business.
Once the floor plan is drawn, millions of grains of colored sand is painstakingly laid into place.
With enormous amount of patience, the monks lay out the sand particles working from the center outwards.
Shortly after their completion, the monks deliberately destroy the mandala to symbolize that nothing lasts forever.
Sources:Drepung Gomang Monastery/Wikipedia/Religion Facts