Grape Agate is the name of a popular mineral specimen. Statistics on their production are shown in the accompanying table. Bolivia, Brazil, Tanzania, Uruguay and Zambia were the countries with the highest production. The United States Geological Survey has estimated the world’s commercial amethyst production between 20. People buy them for home decor, mineral collections, and metaphysical use or just because they like them. The geodes can be small enough to hold in the palm of your hand, or enormous sections of lava tubes that can be several meters long and weigh several tons. Data from the United States Geological Survey. An amazing amount of amethyst is being produced. Much of this production is sold in the form of geodes, crystal plates, crystals, and tumbled stones. The United States Geological Survey estimated the world’s commercial amethyst production between 20.
Some of the amethyst in the Spanish crown jewels may be from this deposit, brought back to Spain by Spanish explorers. The deposit was also known by Native Americans because a few amethyst arrowheads have been found nearby. The mine is well known for producing amethyst with a reddish purple color. Today, the only commercially run amethyst mine in the United States is the Four Peaks Mine in Arizona. Much of it has been as a byproduct of other mining operations. Other productive amethyst deposits are located in Canada, France, India, Madagascar, Mexico, Morocco, Myanmar, Namibia, Russia, South Africa, Sri Lanka, Tanzania, and the United States.Īmethyst has been produced at many locations in the United States. This is a 10.5 x 8.5 millimeter gem, weighing about 3.15 carats. Four Peaks is the most important amethyst mine in the United States and is famous for producing amethyst with a reddish-purple color. Faceting, cabbing and ornamental grade amethyst can be found in all of these locations however, the amount is usually insufficient to support an ongoing mining operation.Īrizona Amethyst: A beautiful reddish-purple amethyst from the Four Peaks Mine, Maricopa County, Arizona. Small amounts of amethyst are found at many locations throughout the world in igneous, metamorphic, and sedimentary rocks. The name "amethyst" is an incorrect varietal name when used as an adjective for chalcedony. Purple chalcedony and lilac chalcedony, are acceptable names for this material. These materials also have a difference in refractive index. There is where you can observe the luster. If you use a hand lens or a microscope to examine the facet junctions on a faceted stone or the boundary between the flat base of a cabochon and its domed sides, you can usually find at least one tiny conchoidal fracture. Quartz has a vitreous luster on conchoidal fracture faces, while chalcedony has a dull luster on conchoidal fracture faces. The name chalcedony is used for microcrystalline quartz - quartz that is in crystals so small that they cannot be seen without the aid of a microscope.įortunately, it is easy to tell the difference between quartz and chalcedony. Why are those names improper? They are improper because purple quartz (amethyst) and chalcedony are two different gemological materials. It is often improperly called "amethyst" or "amethyst chalcedony."
Purple Chalcedony: Chalcedony can occur in a wide range of purple colors. Enormous deposits of amethyst in South America and Africa provide enough amethyst to keep the price low. That makes it durable enough for use in rings, bracelets, earrings, pendants, and any type of jewelry. It is used to produce faceted stones, cabochons, beads, tumbled stones, and many other items for jewelry and ornamental use.Īmethyst has a Mohs hardness of 7 and does not break by cleavage. It is the purple color variety of quartz that has been used in personal adornment for over 2000 years.Īmethyst is the birthstone of February and an important New Age gem. Amethyst is the world's most popular purple gem.
0 kommentar(er)
