Amber is fossilized resin, most often from extinct conifers. Most amber comes from the Baltic coast, encircled by countries of northern Europe and Scandinavia. Most is rich golden yellow-orange in color, but it can also occur in white, green or blue colors. Green amber is popular but rare, and most green amber used in jewelry components has been heat-treated to accentuate the color. Amber has a long history of use, with cups from the Bronze age through intricate rooms in the palace of kings (the "Amber Room" in Catherine the Great's palace). It was often the tears of the gods (Apollo wept amber tears on being banished from Olympus; the Heliades sisters wept amber tears for their brother Phaethon) and represents the division between individual and cosmic energy.
Ammolite is a trade name given to a thin iridescent aragonite shell material found on ammonite fossils. It's a rare material, and most cabochons used in jewelry are from mines in Alberta, Canada. The highest quality ammolite shows play-of-light as dramatic as opal or more so. Like opal, the material is generally sandwiched between a darker base layer and a clear resin coating for protection.
Brass is a metal alloy of copper and zinc whose properties depend on the proportion of the zinc. It has a relatively low melting point and flows easily, making it a good metal for casting. Many jewelry findings have a brass base metal plated with silver or gold or other coatings, though brass jewelry is gaining popularity as a less expensive and attractive option to gold.
Like brass, bronze is a copper-based metal alloy though bronze uses tin rather than zinc and it tends to be a higher percentage copper than brass for a warmer rose gold hue. Like brass, it is a good metal for casting and favored among sculptors because it expands slightly before setting, imparting the finer details of the mould.
Calcite is the most common form of calcium carbonate, from the carbonate group (CO3). Carbonates tend to be soft and generally found everywhere. Most Egyptian alabaster is actually calcite. Large crystals are common, though large translucent pieces are less so. The translucent pieces demonstrate the property of double refraction, where an image through the material appears doubled though shifted. This is due to differing indices of refraction within calcite that "bend" incident light differently.
Copper has the native element with the distinction of being one of the first to be used by humans. Neolithic people used it as a substitute for stone, and Egyptians first cast it in molds. It is found in crystalline and massive aggregate forms. Copper is a secondary mineral that forms as large iron-rich molten rock cools; copper-rich fluids are the last to solidify. It's often found in deposits with other native elements like zinc, lead, gold and silver. In native form it is soft, though many copper alloys are available that are harder. Bronze is copper-tin alloy and brass is a copper-zinc alloy.
Gold captures the imagination as few minerals and elements can; it has been prized throughout civilizations for its beauty and usefulness. It reacts with few materials, so gold-bearing minerals are rare and tend to be localized, though gold as an element is distributed in minute quantities throughout igneous rock. It is estimated that half the world's known gold reserves are found in South Africa. Though there are numerous industrial applications, such as window coatings to reflect infrared radiation and reduce air-conditioning costs for large office buildings, but the most popular use is still within jewelry, as it has been for thousands of years.
Jet is a lignite coal, which is intermediate in terms of carbon-content and hardness in the formation of coal. Coal starts with decaying vegetable matter in the absence of oxygen, forming peat. Peat under pressure results in lignite coal, and additional heat and pressure transform lignite coal to bituminous coal and finally anthracite (most highly metamorphosed and hardest coal). Jet typically originates from wood from the trees of family Araucariaceae, which includes the modern-day monkey puzzle tree and other very tall evergreens like the New Zealand "Lord of the Forest" kauri tree.
Pewter is an alloy of greater than 90% tin with small amounts of copper and antimony. It is a soft metal and has a low melting point, making it suitable for casting - even in a household kitchen! The pewter components I buy are advertised as lead-free, and this is generally the standard for items intended for daily use.
Like gold, silver has a long history with civilizations across the world. The chemical symbol, Ag, comes from the Latin word for silver, argentum, which itself has its origins in Sanskrit meaning "white" and "shining". Mexico is the world's leading producer of silver, though much of the world's supply is generated by refining other metals like copper and zinc. Sterling silver is 92.5 percent silver with another metal such as copper added to increase hardness and durability. Silver is often associated with the Moon and divine wisdom.