Agate Agates in general come in many different forms and are formed in at least five different ways. The main conditions necessary for agate formation, are the presence of silica from denitrified volcanic ash, water from rainfall or ground sources, and manganese, iron and other mineral oxides that form the bands and inclusions.
Rutilated Quartz While most varieties of transparent quartz are valued most when they lack inclusions, some varieties are valued chiefly because of inclusions! The most popular of these is known as rutilated quartz.