Materials & Techniques

Obsidian

GENERAL DESCRIPTION
Obsidian refers to a dark, shiny glass formed in nature by the rapid cooling of lava. Obsidian is widely distributed and has been used since Paleolithic (before 3500 BCE) times for mirrors, weapons, tools, and jewelry. Obsidian is often black in color but may also be red, brown or green. It produces conchoidal fractures when cleaved. Sources of obsidian include Anatolia, Armenia, Ethiopia, Greece (Milos), Italy (Lipari, Eolie), Iceland, the U.S. (Wyoming), Mexico (Teotihuacan), Guatemala (Tikal), and Peru.

Alabaster

GENERAL DESCRIPTION
Alabaster refers to a fine-grained marblelike variety of gypsum that is easy to carve but is rather fragile; it has been used as a sculpture material, in ornamental building work, for vases and small decorative carvings, and also powdered for use as a paper filler and paint pigment called mineral white or terra alba. Alabaster is usually a translucent white or pink but may also be a muted red, yellow, or gray.

Copal

GENERAL DESCRIPTION
Copal refers to the general term for a variety of hard, natural resins obtained directly from various tropical trees of the genera Hymenaea and Agathis. Copal is characterized as a hard, translucent odoriferous resinous substance in an intermediate stage of polymerization and hardening between gummy resins and amber. Copals contain communic acids, communol, resene, and volatile oil.

Mixtec and Aztec Masks: Turquoise Mosaic

GENERAL DESCRIPTION
A mosaic is composed of small, usually colored pieces of inlaid stone, glass, or other material that together create an image or design. The art form of turquoise mosaic originated among the Mixtec of Oaxaca, and the tradition continued among the Aztecs. Mosaic enhanced the surfaces of masks, headdresses, shields, sacrificial knives, helmets, pectorals, staffs, and a variety of other objects. The tedious process involved grinding tiny tiles (tesserae)—predominately turquoise but includ

Oxidation

GENERAL DESCRIPTION
The process of "setting out" a design on a piece of metal by dipping it into a solution of boiling water and sodium sulphide, which oxidizes the silver and produces a deposit of black silver sulphide. 
 

Direct carving

GENERAL DESCRIPTION
Direct carving is the process of carving away the block of stone (or other material) to create a sculpture. This method had a resurgence in the 20th century when modernist artists rejected of traditional sculptural techniques that required multiple assistants working within an artist's workshop to produce monumental marble works or multiple bronze casts.

Sheffield Plate

GENERAL DESCRIPTION
An older form of plated silver originally made during the 18th century in Sheffield, England, by rolling sheets of silver over a copper base.