Gallstones can lurk inside your gallbladder. Many people have gallstones and never know it. Gallstones are hard deposits in your gallbladder, a small organ that stores bile, which is a digestive fluid made in the liver. Gallstones may consist of cholesterol, salt, or bilirubin, which is discarded red blood cells. Gallstones range in size. They can be as small as a grain of sand or as large as an apricot.

What Causes Gallstones?
The components in bile can crystallize and harden in your gallbladder, leading to gallstones. According to researches, 80 percent of gallstones are made of cholesterol. The other 20 percent of gallstones are made of calcium salts and bilirubin. These are known as pigment stones.

Cholesterol Stones:
Gallstones may develop when there is too much cholesterol in the bile secreted by your liver. Bile usually dissolves or breaks down cholesterol. However, if your liver makes more cholesterol than your bile can dissolve, hard stones may develop.

Bilirubin:
Bilirubin is a chemical produced when your liver destroys old red blood cells. Some conditions, such as Cirrhosis of the liver and certain blood disorders, cause your liver to produce more bilirubin than it should. Stones form when your gallbladder cannot break down the excess bilirubin. These hard substances are also called pigmented stones.

Concentrated Bile:
Your gallbladder needs to empty bile to be healthy and function properly. If it fails to empty its bile content, the bile becomes overly concentrated, which causes stones to form.

What Are the Symptoms of Gallstones?
You may not experience any symptoms if you have gallstones. According to researches, 80 percent of people who have gallstones don’t have any pain at all. These are called "silent" gallstones. Your doctor may find these stones in your gallbladder from X-rays or performing surgery on your abdomen. Some people do have gallstone symptoms. The most common symptom of gallstones is pain in the right upper quadrant of your abdomen. The pain often radiates to your back or right shoulder or shoulder blade.