About two weeks pass before the blossoms fade.
What transpires to lithops once they flower?
Every year, lithops grow a fresh pair of leaves. The old leaves must wither in order for the new ones to develop because they only have one pair of leaves at a time. New leaf growth typically begins following the blooming season. Lithops will go into dormancy for a period after they flower in order to be ready for fresh growth. Old leaves will continue to provide the plants with nutrition, and ultimately, new pairs of leaves will push through the crack left by the old ones.
Your Lithops may occasionally produce new leaves without blooming. Most of the time, it is difficult to determine the precise cause, but the Lithops may be in the early stages of their growth cycle.  
Checking the leaves of your Lithops is one technique to see whether it is producing new leaves. The outer leaves are likely in the process of shredding if they feel mushy and spongy to the touch. You will quickly notice new leaves growing after a few days. If not, it can simply be underwatering. Do not water your Lithops during this time until the old leaves have fully withered.
Do Lithop flowers have nighttime hours?
The green rock plant, or Lithops viridis, is a species of plant in the Aizoaceae family. Because of its rock-like leaves, it is safe from harm. It has succulent leaves. This is one of the few Lithops with green leaves; the daisy-like flowers close at night.