Blessed candles are sacramentals used in the liturgy of the Church. They were used from very early times and according to St. Jerome were symbols of joy.
There are no strict rules concerning the size or shape of candles. However, those used during liturgical functions and Exposition of the Blessed Sacrament contain more than 50 percent of pure beeswax, but the general rule when used in liturgy, candles should be of “a worthy material and suited to their purpose.” So-called vigil or votive lights are not blessed as a rule.
The large, that is, tall, candle that is blessed and lighted on the Vigil of Easter and is symbolic of the risen Christ is called the Paschal Candle. It is placed on the Gospel side of the altar and is lighted during the Easter Season.
The candle itself is generally highly ornamented with colored wax forms or symbols, but it must have, in the form of a cross, five imbedded or mounted grains of incense representing the wounds of Christ.
The Paschal Candle is used at the ceremony of blessing the baptismal water, at which time a part of the candle is immersed into the water. This candle is then lit during baptisms and funeral liturgies throughout the year. (7:23)