Florida State Stone
Agate, a form of chalcedony, forms in rounded nodules or veins when quartz replaces organic material in an organism. In addition to stones, fossil corals and mollusks can also agatize, as is the case with agatized coral. The result is a pseudomorph, meaning the replacement took place without the loss of the original form of the coral, its outer skeleton. About 35 to 40 million years ago, seas covered what is now the state of Florida. Coral reefs in these seas fossilized into agatized coral.
A STATE SYMBOL
Agatized coral is indigenous to Florida. The Florida Legislature designated agatized coral as the state stone in 1979.
The term "chalcedony" is derived from the name of the ancient Greek town Chalkedon (Chalcedon in English) in Asia Minor, which today is the Kadıköy district of Istanbul, Turkey.
The word "agate" comes from the site where it was originally reported, the Achates River, or Αχάτης in Greek, which is now known as the Dirillo River in Sicily, Italy. The Greek naturalist and philosopher Theophrastus discovered agates sometime between the 4th and 3rd centuries BCE. Agates were widely used in the ancient world.
FORMATION AND OCCURRENCE
Agates are normally associated with volcanic lava rocks and are also found in some metamorphic rocks. Silica-rich water percolates through the rock, escaping as gas and depositing traces of the silica in the rock’s crevices. Layers are formed and eventually the rounded nodules called agates result.
Much of Florida’s agatized coral formed as limestone geodes in the Oligocene-Miocene Hawthorn Group sediments. These sediments existed 12 to 16 million years ago in the middle Miocene period.
Agates are widespread, occurring in most areas of the world. In addition to the site where the mineral was first reported in Sicily, major agate locations include Argentina, Botswana, Brazil, Germany, Mexico, Morocco, Poland, the U.S., and other regions of Italy. The important gem region of Idar-Oberstein, in the Hunsrück Mountains in Rheinland-Pfalz, Germany, got its start as a source for agate thousands of years ago.
Florida’s agatized coral occurs in the Tampa Bay area, as well as in limestones along the Econfina, Withlachoochee, and Suwannee Rivers. Agatized coral can also be found in southern Georgia.
Early humans made weapons and tools from many varieties of chalcedony including agate, agatized coral, flint, jasper, and petrified wood. Because of its abundance, durability, and beauty, types of chalcedony were some of the earliest raw materials used by humans. The earliest recorded use was for projectile points, knives, tools, and containers such as cups and bowls.
From antiquity through the Renaissance period, collecting bowls made of agate was a popular hobby. In fact, this hobby is what led to the growth of the gemstone industry in the Idar-Oberstein district of Germany, one of the world’s leading centers for gemstone cutting and trading.
Today, agate is chiefly made into stones and used for ornamental purposes, such as in brooches and pins, pendants and charms, beads, mosaics, and dream catchers. Agate is one of the most varied and most popular gemstones. Agate also has more utilitarian applications, including inkstands, mortars and pestles, and letter openers. All types of agates, including agatized coral, are popular among collectors as mineral specimens.
Agate has been believed for centuries to protect the wearer or holder of the stone from a wide variety of dangers and to bring good fortune. Because it has been known and used by humans for millennia, the supposed benefits of agate are innumerable and cross into many cultures.
Agate is the mystical birthstone for September and the birthstone for the zodiac sign of Gemini. Agate is given for the 12th and 14th wedding anniversaries.
Chemical Formula: SiO2
|Author: World Trade Press|