Boyd’s Bible Dictionary:
(high). First altars were simple memorial piles (Gen. 8:20; 12:7; 26:25; 35:1). Afterward to lay sacrifices upon (Ex. 17:15-16; 27:1-8). Usually built of earth or stone (Ex. 20:24-26); but sacrificial altars quite elaborate (Ex. 40:26-33). Still more elaborate in Solomon’s Temple (1 Kings 8:64; 2 Chron. 7:7). Altar fires to burn perpetually (Lev. 6:12-13). Altar of Incense, called “golden” to distinguish it from Altar of Sacrifice, called “brazen” (Ex. 30:1-10; 40:5, 1 Kings 7:48; 1 Chron. 28:18).
Concise Bible Dictionary:
The altar of incense was made of shittim wood, overlaid with pure gold (Ex. 30:1-5; Ex. 37:25-28). It was in length and in breadth 1 cubit, and in height 2 cubits. In Solomon’s temple this altar was made of cedar overlaid with gold, but its size is not given. In the temple described by Ezekiel the altar of incense is 2 cubits in length, and 3 cubits in height (Ezek. 41:22). The Altar of Incense is also called the GOLDEN ALTAR. Its situation was in the holy place, with the golden candlestick and the table of shewbread.
On this altar holy incense was to be burnt both morning and evening, typical of the Lord Jesus being a perpetual sweet savor to God. It was by the side of this altar that the angel appeared to Zacharias when he announced the conception and birth of John the Baptist (Luke 1:11).