What is Citrine? 
Citrine is a transparent, yellow variety of Quartz, ranging in color from pale to golden yellow, honey or almost brown, and may contain rainbow or sparkle inclusions. The name comes from the French word citron, meaning lemon.
 
What are the benefits of critine?
Citrine has several healing benefits:
Acts as a manifesting stone: A manifestation, used in the context of working with crystals, refers to a person's projecting and programming her intention into the crystal being worked with. In essence, the crystals absorb what is called your manifestation wishes—your deepest hopes and dreams—then help make them a reality.
Dispels anger and gives optimism: All of this light that citrine provides means that citrine cannot tolerate negativity. Spread some crystals in your garden to bring light to your plants and help them grow. Being in contact with citrine, as it channels the light-giving power of the sun, helps you cast aside negative feelings and aids any sun-loving entities (such as plants) to grow.
Aids digestion: This spiritual light also helps to detoxify your system, says Crystal Informaition.com, which in turn, helps to ease and aid digestion.
Gives mental clarity: Being in contact with this light-generating crystal is thought to help boost your creativity, visualization powers, and confidence.
 
Why do crystals vary in shape and size?
Crystals are minerals that have grown into regular, geometric solids bounded by flat faces.In most cases, minerals grow into irregular, random shapes.