Larger | Spin | 3D. Indium foil. Indium is often used to form air-tight seals between glass components because it is soft enough to mold itself to the shape of the glass, and because unlike rubber or other organic seal materials it is really 100% gas-tight and it doesn't release volatile compounds of its own.
Melasma is a chronic skin disorder that results in symmetrical, blotchy, brownish facial pigmentation. It can lead to considerable embarrassment and distress. This form of facial pigmentation is sometimes called chloasma, but as this means green skin, the term melasma (brown skin) is preferred.
Below the age of 20, acne can cause dark spots due to scarring and red marks left by the infection. Skin Diseases That Cause Dark Spots Melasma: Itâs one of the commonest causes of grayish patches on the face. It mostly affects the forehead, cheeks, or the area between your mouth and nose.