Pearls are small, round, and lustrous objects that are produced by certain types of mollusks, which are invertebrate animals that belong to the phylum Mollusca. Mollusks include a wide range of species, including oysters, clams, mussels, snails, and octopuses, among others.
While all mollusks have the ability to produce pearls, only a few varieties are able to create gem-quality pearls that are suitable for use in jewelry. These include the oysters that produce akoya pearls, the freshwater mussels that produce freshwater pearls, and the South Sea and Tahitian pearls, which are produced by large saltwater oysters.
Pearls are formed when an irritant, such as a grain of sand or a parasite, enters the mollusk and becomes trapped inside its shell. In response to the irritant, the mollusk secretes a substance called nacre, which coats the irritant and eventually forms a pearl.
The quality of a pearl is determined by a number of factors, including its size, shape, color, and luster. High-quality pearls are prized for their beauty and are used in a variety of different types of jewelry, including necklaces, earrings, and bracelets.
Marcasite is a mineral that is made up of iron sulfide and has an orthorhombic crystal structure. It is known for its golden yellow color and metallic luster, but it is very brittle and not suitable for use in jewelry. Instead, what is often referred to as "marcasite" in jewelry is actually pyrite, which is also known as "fool's gold," that has been faceted to mimic the appearance of diamonds.
Marcasite has been used in jewelry since around 1700, and it is usually found mounted in silver. It has remained popular in high-quality fashion jewelry due to its attractive color and luster. In antique jewelry, marcasite can be distinguished from cut steel faux gems because marcasite is typically bead or prong-set, like a gemstone, while cut steel is usually riveted.
Silver is a white metallic element that is known for its excellent conductivity of heat and electricity. It is represented on the periodic table of elements by the symbol Ag, and it is a member of the noble metals, which are known for their excellent resistance to oxidation.
Silver is a relatively soft metal, with a hardness that is intermediate between gold and copper. It is more malleable and ductile than gold, which means that it can be easily shaped and molded into various forms. However, it is not as hard as copper, which means that it is more prone to scratches and other types of damage.
Because of its softness, silver is usually alloyed with another metal to harden it enough to maintain the desired shape and details when it is used in jewelry and other decorative objects. This helps to give it the necessary strength and durability for use in these types of applications.
Throughout history, silver has played a prominent role in the production of jewelry and objets d'art. It is prized for its beauty and versatility, and it is often used in a wide variety of different types of jewelry, including rings, earrings, pendants, and bracelets. It is also used in decorative objects, such as candlesticks, vases, and other decorative items.