The Salt Lake Temple Earth Stones
The Earth Stones are located along the base of the Salt Lake Temple at the bottom of each of the pilasters, and on the towers. The original plan for the temple included having the stones carved in a sequence to depict the different faces of the Earth. This plan had to be abandoned once the decision was made to use granite, because the stone was too hard to allow intricate details. The Earth stones have several symbolic meanings.
The Earth Stones represent the gospel of Jesus Christ being brought to every nation, kindred, tongue and people on the Earth. The Earth Stones are set at the base of the temple. This is to denote the Earth being God's footstool as He sits on His throne in Heaven. (Acts 7:49). It also suggests the need of the people on the Earth to look to Heaven.
The placement of the Earth Stones at the bottom of the pilaster, below the Moon Stones and Sun Stones, typifies the Telestial Kingdom, or the lowest of the Three Degrees of Glory. Normally this kingdom is portrayed using stars, but in this case it's a reflection of the temple teaching that because of the Fall of Adam the Earth is currently in a Telestial state.
The Earth Stones incorporate the squared circle motif. This symbol entails the square representing the four corners of the Earth, and the circle representing the Celestial Dome. Combined, the symbol means a place where Heaven and Earth meet. This is apropos for the temple, since patrons symbolically enter God's Kingdom, and the priesthood blessings given therein are binding on Earth and in Heaven.