Glossary of Terms & Facts

Pendant

Overview and History of Pendants Pendants are among the oldest recorded types of bodily adornment Ancient Egyptians commonly wore pendants, some shaped like hieroglyphs Pendants can serve several functions, such...

Pectoral (Ancient Egypt)

Definition and Types of Pectorals The pectoral is a wide piece of jewelry. The word for pectoral can also include amulets. The pectoral can be represented by different hieroglyphs. Some...

Pearl

General Information about Pearl Pearl is a carbonate mineral composed of calcium carbonate (CaCO). It belongs to the orthorhombic crystal system. Pearls come in various colors such as white, pink,...

Paragon (diamond)

Paragon Diamond Largest flawless diamond in the world Weighs 137.82 carats (27.564g) Tenth largest white diamond globally Mined in Brazil Exceptional white, flawless stone of great size Acquisition and Cutting...

Organic compound

Definitions and History of Organic Compounds Organic compounds contain carbon-hydrogen or carbon-carbon bonds. Inorganic compounds may contain carbon but lack carbon-hydrogen or carbon-carbon bonds. Alkanes and their derivatives are universally...

Optics

Introduction to Optics Optics is the branch of physics that studies the behavior and properties of light. It includes the interactions of light with matter and the construction of instruments...

Opal

General Information about Opal Opal is a mineraloid composed of hydrated silica. It has a hardness of 5.5-6 on the Mohs scale. Opal can have a luster ranging from subvitreous...

Opacity (optics)

Opacity Definition and Characteristics Opacity is the measure of impenetrability to electromagnetic or other kinds of radiation, especially visible light. It describes the absorption and scattering of radiation in a...

Onyx

Definition and Composition of Onyx Onyx is a type of mineral and a form of chalcedony. It belongs to the quartz family and is composed of fine-grained silica minerals. Onyx...

On Weights and Measures

Background of 'On Weights and Measures' Compiled in 392 AD in Constantia by Epiphanius of Salamis Written at the request of a Persian priest, sent by the Roman emperor in...

Olivine

Identification and Occurrence Olivine is named for its typically olive-green color, thought to be a result of traces of nickel. Translucent olivine is sometimes used as a gemstone called peridot....

Obsidian

Origin, Properties, and Occurrence of Obsidian Obsidian is a volcanic glass formed when lava cools rapidly with minimal crystal growth. It is produced from felsic lava rich in elements like...