The third Foundation Stone of New Jerusalem.

Chalcedony is a cryptocrystalline variety of quartz (having crystals so small they cannot even be seen with a microscope). It has a waxy luster and can be semi-transparent to translucent. There are many varieties of chalcedony, but most of them are known under different names and are distinguished by their color (i.e. chrysoprase is apple green, carnelian is red, onyx is black and white stripes, sardonyx is red and white stripes, and agate contains many multi-colored bands). Specimens that are called by the name chalcedony are generally either a milky white, light gray, blue, or yellowish brown in color. Chalcedony in gem form is generally cut in cabochons, as it is not well suited for faceting. In Biblical times, chalcedony was used extensively in the carving of seals, signet rings, beads, bowls, goblets, glasses, and other household objects. The word “chalcedony” is derived from the name of the ancient Greek town, Chalkedon, in Asia Minor, in modern English usually spelled Chalcedon.

Agates are a form of chalcedony that are banded or lined in a variety of patterns of colored layers. Colors range from white to dull yellow, red, brown, orange, blue, black and gray. The Hebrew word for agate is ‘shebo’ which literally means ‘to flame, split into tongues.’ ‘Agate’ comes from the Greek word ‘achates’, which is the name of the river in Sicily where agate was mined in abundance as early as 3000 BC. Agate is named as the second stone in the third row of the High Priest’s breastplate. Agates were highly prized among ancient civilizations. It was fashioned into beads, pins, brooches, signet rings, goblets, cups, bottles, bowls, and carved figurines. Large amounts of agate have been found in archaeological digs of Sumer, dating back to 3500 BC. Theophrastus (372-287 BC) appears to have been the first man to write about agates. In his work, ‘Concerning Stones’, he notes that agate is a “marvelously beautiful stone” and usually sold at high prices.

Native American Indians believed chalcedony was a sacred stone and used in the spiritual ceremonies of the tribe. It is thought to increase vitality, stamina, and endurance and to promote emotional balance and charity while relieving melancholy, fever, gallstones, and eye problems. Gem folklore says that agates are powerful stones of harmony and healing, protection and prosperity. Agate is believed to discern truth, accept circumstances, and is a powerful emotional healer. Legend says that Agate improves memory and concentration, increases stamina and encourages honesty.

One of the earliest writers to associate with the apostles the symbolism of the gems given in Revelations is by Andreas, bishop of Caesurae. He gives a brief description of the stones, which is recounted in George F. Kunz's book The Curious Lore of Precious Stones (1913). The chalcedony represents St. Andrew.