Chapter V-D. Altar
259. At the altar the sacrifice of the cross is made present under sacramental signs. It is also the table of the Lord and the people of God are called together to share in it. The altar is, as well, the center of the thanksgiving that the Eucharist accomplishes. 
260. In a place of worship, the celebration of the Eucharist must be on an altar, either fixed or movable. Outside a place of worship, especially if the celebration is only for a single occasion, a suitable table may be used, but always with a cloth and corporal.
261. A fixed altar is one attached to the floor so that it cannot be moved; a movable altar is one that can be transferred from place to place.
262. In every church there should ordinarily be a fixed, dedicated altar, which should be freestanding to allow the minister to walk around it easily and Mass to be celebrated facing the people. It should be so placed as to be a focal point on which the attention of the whole congregation centers naturally. 
263. According to the Church's traditional practice and the altar's symbolism, the table of a fixed altar should be of stone and indeed of natural stone. But at the discretion of the conference of bishops some other solid, becoming, and well crafted material may be used.
The pedestal or base of the table may be of any sort of material, as long as it is becoming and solid.
264. A movable altar may be constructed of any becoming, solid material suited for liturgical use, according to the traditions and customs of different regions.
265. Altars both fixed and movable are dedicated according tot he rite described in liturgical books, but movable altars may simply be blessed.
266. The practice of placing under the altar to be dedicated relics of saints, even of non-martyrs, is to be maintained. Care must be taken to have solid evidence of the authenticity of such relics.
267. Other altars should be fewer in number. In new churches they should be placed in chapels separated in some way from the body of the church.