The glass marimba is a type of idiophone also known as a vitrephone or crystallophone. Marimba translates to "a xylophone-like instrument" from an African language, probably Bantu. The glass keys are made of either hard glass (plate glass) or soft glass (stained glass). The keys are resonated with either a single open top box or individual resonators for each key. Mallets used to play the marimba can be constructed using a compressed silicone ball (bouncy ball) attached to one end of a wooden or synthetic dowel. These mallets bring out the purest sound from glass marimba. Other types of mallets are used for different effects. The tuning system of a glass marimba can be whatever is desired. Glass marimbas are utilised by the Brazilian percussion ensemble, Uakti.