If you’ve been following this rite with us, some of these considerations have already been addressed in the rites for dedicating a church (RDCA, chapter II) and the dedication of an altar (chapter IV). There is a seven-section introduction for the blessing of an altar, which gives details on the proper distinctions to be made for movable altars:
1. ‘A fixed altar is one so constructed that it is attached to the floor so that it cannot be moved; a movable altar can be transferred from place to place.’ (GIRM 298)
A fixed altar is to be dedicated according to the rite described in chapter four. A movable altar also deserves religious respect because it is a table set aside solely and permanently for the eucharistic banquet. Consequently, before a movable altar is put to use, if it is not dedicated, it should at least be blessed with the following rite. (cf. GIRM 300)
2. A movable altar may be constructed of any solid material that the traditions and culture of different regions determine to be suitable for liturgical use. (cf. GIRM 301)
3. To erect a movable altar what is laid down in the Introduction to chapter four, nos. 6-10, is to be followed, with the necessary modifications. However, it is not permissible to place the relics of saints in the base of a movable altar.
4. It is appropriate that a movable altar be blessed by the bishop of the diocese or by the priest who is rector of the church.
5. A movable altar may be blessed on any day, except Good Friday and Holy Saturday. As far as possible, a day should be chosen when the people can be present in large numbers, especially a Sunday, unless pastoral considerations suggest otherwise.
6. In the rite of blessing a movable altar the Mass is the Mass of the day.
7. The altar should be left bare until the beginning of the liturgy of the eucharist. Hence a cross (if need be), and altar cloth, candles, and everything else necessary to prepare the altar should be on hand at a convenient place in the sanctuary.
The rubrics, texts, and ritual directions contained in the rite itself (8-13) are virtually identical to what we saw in the Blessing of a Church (Chapter V, 20-25).