- Typically reserved to refer narrowly to the cultures of the native peoples of the United States and Canada, excluding the Eskimos and Aleuts. For the indigenous peoples of Canada use the term "First Nations." For the broader concept of the cultures of any native peoples of Central America, South America, North America, or the West Indies who are considered to belong to the Mongoloid division of the human species, use "Amerindian (culture)."
- Refers to the cultures of the continent of North America, which is bounded by the Atlantic Ocean, the Pacific Ocean, the Arctic Circle, and Central America. In classifications schemes based on physical geography, Central America, and North America are parts of the same continent.
- Pieces of hard material, typically stone or metal, sharpened to have a cutting edge or penetrating point for use as projectiles or the heads of projectile weapons.
- Sandstone that is rich in silica, particularly as free silica as opposed to silicates; the silica characterizes the cement or matrix which binds together the quartz particles of which sandstone is mainly composed. Pure siliceous sandstone is chemically inert, making it able to withstand a smokey environment; it is therefore a popular building stone in industrial areas. It is also hard and durable but difficult to work. Pure siliceous sandstone is white or cream in color; colors are due to impurities: yellow and red colors are due to the presence of iron oxides; green from glauconite; and black from manganese dioxide.
Click an image to view a larger version
Click a portfolio name to view all the objects in that portfolio
This object is a member of the following portfolios: