Pigments mineral color

Pigments, minerals, gemstones, glasses, and many related materials are colored by impurity defects that absorb some of the incident white light, leaving a depleted spec-hum to color the solid. Colors in these materials are thus characterized by the absorption spectrum of the solid. Common inorganic colorants are the transition-metal and lanthanide metal ions. The colors ate characteristic of the ions themselves and are due... 

The preparation of painter s pigments is also treated, with many vegetable as well as mineral colors in use.56... 

North American archaeological sites reflect the use of colorants, exemplified by the abundance of die inorganic mineral pigment red ochre in domestic and mortuary contexts in sites from the Clovis through the Mississippian periods (10000 B.P.-1400 A.D.). Typically the presence of these accumulations of pigment minerals is interpreted as material used in ceramics, or for body painting. Color on textiles is not usually considered. 

In analyzing the fibers at a microscopic level, the general fiber classes were identified (hair or bast). Furthermore, adherence of particles to the fibers, be they mineral colorant or soil was determined and when possible identified with the help of the particle atlas (38). The previously created control mounts were used as comparative materials to the unknown mineral or pigment deposits that were observed in foe artifact samples. 

Metallic pigments, inorganic Mineral colors and pigments... 

Ricketson Mineral Colors. [DCS Colc Supply] Iron oxide pigments for mortar and cements. 

A red mineral color caused by chromium was also seen long before the days of Lehmann, Pallas and Vauquelin. The mineral corundum is aluminum oxide in a clear, transparent form. The beautiful red ruby is corundum contaminated with chromium. Color in minerals is caused either by ion complex formations or by pigmentation. Therefore one metal can give different colors to a colorless mineral. If the corundum contains iron or titanium instead of chromium the precious blue stone sapphire is obtained. 

Standard screen printing inks consist of a thick carrier liquid (binder) and finely ground mineral pigments for color, as well as various types of thinner agents to enable the ink to flow and wet to the surface of the substrate. Given the many different materials screen printing interfaces with, there are just as many molecular-ly-different ink formulations to optimize the adhesion of each to these various materials. 

To meet the functional requirements in the end application, additives are often compounded into the engineering plastics. These additives could be glass fibers for increased stiffness and strength, impact modifiers for improved impact toughness, mineral fillers for stable dimensions, stabilizers to prevent UV and heat ageing, and last, but certainly not least, various pigments or colorants to obtain the required color of the final part. All of these will influence the transparency of the compound. 

Other. A large variety of additives are used in paper-coatiag colors primarily to modify the physical properties of the colors (102). At high soHds concentrations in water, mineral pigment particles tend to associate and form viscous pastes. Dispersants (qv) are used to prevent this and to provide low viscosity slurries. Common dispersants include polyphosphates and sodium polyacrylate [9003-04-7]. Various water-soluble polymers are added to coatiag colors and act as water-retention agents and as rheology modifiers. 

Consumer articles often use colorants (qv), reodorants, or finishing agents. Carbon black (qv) provides the best technological properties for industrial appHcations, so most mbber articles are black. Red iron oxide or other inorganic pigments are used to color mineral-filled articles. Organic... 

The first chromium compound was discovered in the Ural mountains of Russia, during the latter half of the eighteenth century. Crocoite [14654-05-8] a natural lead chromate, found immediate and popular use as a pigment because of its beautihil, permanent orange-red color. However, this mineral was very rare, and just before the end of the same century, chromite was identified as a chrome bearing mineral and became the primary source of chromium [7440 7-3] and its compounds (1) (see Chromiumand chromium alloys). 

---