Cobalt is used in its carbonate (CoCO3) or oxide (Co3O4) forms as a colouring agent for ceramics fired in oxidation and reduction atmospheres. It produces blue colours ranging from low saturation light shades to intense high saturated blues. In glazes with multiple colourants, cobalt and magnesium oxide (MgO) yield blue-violet and purple, whereas cobalt and manganese oxide (MnO2) make a deep black. Today, cobalt is still used to produce underglaze blue-and-white porcelain in contemporary ceramic workshops.

青花瓷在繪製上色時，會使用碳酸鈷（CoCO3）或氧化鈷（Co3O4）兩種型態的鈷料，分別經氧化和還原氣氛燒製，呈現深度不一的藍色。調製青料時，工匠也會加入其他化學物質，與鈷料相混合，如加入氧化鎂（MgO）可加深紫色，加入氧化錳（MnO2）則顯深黑色。時至今日，鈷仍然是陶瓷作坊燒造青花瓷的主要原料。