Is gold a liturgical color for vestments at Mass?

When looking at a liturgical calendar gold is not listed, but in practice, many priests wear gold vestments during the Easter and Christmas seasons.

During the Easter and Christmas seasons in particular, many priests wear gold vestments at Mass.

However, when looking at the Roman Missal or a liturgical calendar, gold is never listed as a color.

Technically speaking, the color gold is not the default liturgical color for the Easter season. White is the color, as Dom Prosper Gueranger explains in his Liturgical Year.

White is appropriate to the Resurrection: it is the mystery of eternal light, which knows neither spot nor shadow; it is the mystery that produces in a faithful soul the sentiment of purity and joy.

The General Instruction of the Roman Missal (GIRM) explains that white is the color for Easter, as well as other similar feasts of joy:

The color white is used in the Offices and Masses during Easter Time and Christmas Time; on the Solemnity of the Most Holy Trinity; and furthermore on celebrations of the Lord other than of his Passion, celebrations of the Blessed Virgin Mary, of the Holy Angels, and of Saints who were not Martyrs; on the Solemnities of All Saints (November 1) and of the Nativity of St. John the Baptist (June24 ); and on the Feasts of St. John the Evangelist (December 27), of the Chair of St. Peter (February 22), and of the Conversion of St. Paul (January 25).
GIRM 346

At the same time, the GIRM does allow gold for any festive liturgy.

The colors gold or silver may be worn on more solemn occasions in the Dioceses of the United States of America.

Previously these vestments were made from gold thread, as The American Ecclesiastical Review explains:

Decree 3191 of this Sacred Congregation contains this question and answer. “Is it possible to use vestments of yellow color whether made of silk or of gold thread in the place of white green, red, and violet especially, in poor churches which are not able to afford vestments in the various colors?” The reply was that vestments of the color of yellow were forbidden, that vestments made of gold thread were permitted, but even then not for violet.

Gold can then be used on any major feast, even if that feast is a martyr and a priest would normally have red vestments worn at Mass.

The main intention behind this permission is to “bring out the best” when it comes to celebrating a major feast and gold is considered a more valuable material used in the making of vestments.