Stainless Steel Necklace and Earrings Sets
A ceramic is an inorganic compound, non-metallic, solid material
comprising metal, non-metal or metalloid atoms primarily held in
ionic and covalent bonds. This article gives an overview of ceramic
materials from the point of view of materials science.
The crystallinity of ceramic materials ranges from highly oriented
to semi-crystalline, vitrified, and often completely amorphous
(e.g., glasses). Most often, fired ceramics are either vitrified or
semi-vitrified as is the case with earthenware, stoneware, and
porcelain. Varying crystallinity and electron consumption in the
ionic and covalent bonds cause most ceramic materials to be good
thermal and electrical insulators (extensively researched in
ceramic engineering). With such a large range of possible options
for the composition/structure of a ceramic (e.g. nearly all of the
elements, nearly all types of bonding, and all levels of
crystallinity), the breadth of the subject is vast, and
identifiable attributes (e.g. hardness, toughness, electrical
conductivity, etc.) are hard to specify for the group as a whole.
General properties such as high melting temperature, high hardness,
poor conductivity, high moduli of elasticity, chemical resistance
and low ductility are the norm, with known exceptions to each of
these rules (e.g. piezoelectric ceramics, glass transition
temperature, superconductive ceramics, etc.). Many composites, such
as fiberglass and carbon fiber, while containing ceramic materials,
are not considered to be part of the ceramic family.
A pearl is a hard glistening object produced within the soft tissue
(specifically the mantle) of a living shelled mollusk or another
animal, such as a conulariid. Just like the shell of a mollusk, a
pearl is composed of calcium carbonate (mainly aragonite or a
mixture of aragonite and calcite) in minute crystalline form, which
has been deposited in concentric layers. The ideal pearl is
perfectly round and smooth, but many other shapes, known as baroque
pearls, can occur. The finest quality natural pearls have been
highly valued as gemstones and objects of beauty for many
centuries. Because of this, pearl has become a metaphor for
something rare, fine, admirable and valuable.
The most valuable pearls occur spontaneously in the wild, but are
extremely rare. These wild pearls are referred to as natural
pearls. Cultured or farmed pearls from pearl oysters and freshwater
mussels make up the majority of those currently sold. Imitation
pearls are also widely sold in inexpensive jewelry, but the quality
of their iridescence is usually very poor and is easily
distinguished from that of genuine pearls. Pearls have been
harvested and cultivated primarily for use in jewelry, but in the
past were also used to adorn clothing. They have also been crushed
and used in cosmetics, medicines and paint formulations.
Packaging & Delivery
Shipping method: DHL / FedEx / Ups / ePacket / China Post
Time of Shipping: It will take about 7 working days by
DHL/Fedex/Ups to arrive. about 10-15 working days by Epacket/China
Post to arrive.
Delivery Time: In 7 working days after received the payment
Package: Plastic Bag + Bubble Wrap + Carton Box
Main market: America and Europe
You may track the package during the transit or delivery, please
leave your moblie phone on the order to make sure that the postman
will find you when delivering the package.
The package is sometimes delayed during the delivery, but please
keep waiting or contact us when it is happened.
Any question please feel free to contact us.