Lapis

Lapachic acid Lapacol [84-79-7 Laparoscope Lapelloy Lapis Lazuli Lapis lazuli [1302-85-8] Laplace pressure Laplace s equation... 

Discredited Synthetics. There are several materials that have in the past been considered to be synthetics, but were found on closet examination not to deserve such a designation, being merely imitations. Examples include imitation coral, lapis la2uli, and turquoise, all made by ceramic processes. This same point has been raised (17) with respect to synthetic opal, which does contain some substances not present in natural opal and somewhat less water. However, the composition of natural opal is quite variable and is usually intermixed with significant amounts of rock-derived materials hence the synthetic designation is usually retained. 

Ultramarine Pigments. Ultramarines are derived from lazurite [1302-85-8] (lapis lazuli), a semiprecious stone, which was the natural source of ultramarine blue for hundreds of years. Ultramarines can be prepared in many shades. Examples of commercially significant ones ate ultramarine blue, ultramarine violet, and ultramarine pink. The ultramarine pigment having a green shade can also be prepared but it is not commercially available. The first German patent issued in 1877 was for the manufacture of ultramarine red (42). 

This will give a conservative relief valve area. For compressible fluids use Ah corresponding to lAPi if head difference is greater than that corresponding to Pi (since sonic velocity occurs). If head difference is below that corresponding to APi use actual Ah. 

Azulminsaure,/. azulmic acid, azur, azurblau, azum, a. azure, sky-blue. Azurstein, m. lapis lazuli, azyklisch, a. acyclic. 

HoUen-dl, n. curcas oil (from Jatropha curcaa) , castor oil worst grade of olive oil. -stein, m. lapis infemalis, Itmar caustic (silver nitrate). 

Lasur, /. azure azurite glazing, glaze. — m. lapis lazuli. 

Lasurit, m. azurite lapis lazuli, lasur-lack, m. transparent varnish, -schleif-lackf m. transparent flatting varnish, -spat, m. lazuUte. 

Lasorstein, m. lapis lazuli. — unechter —, false lapis lazuli, chessylite. lateinisch, a. Latin roman (letters). 

FIGURE 15.15 The blue stones in this ancient Egyptian ornament are lapis lazuli. This semiprecious stone is an aluminosilicate colored by S2 and S, impurities. The blue color is due to S3 and the h i nt of green to S2. ... 

The sulfur analog of hydrogen peroxide also exists and is an example of a polysulfane, a catenated molecular compound of composition HS—S —SH, where n can take on values from 0 through 6. The polysulfide ions obtained from the polysulfanes include two ions found in lapis lazuli (Fig. 15.15). 

C03-0102. Calculate the mass percentages of all of the elements in the following semiprecious minerals (a) lapis lazuli, N34 AI3 Si3 O12CI (b) garnet, Mgg AI2 (Si04)3 (c) turquoise,... 

Zeolites are structurally related to colorless sodalite, Na4Cl[Al3Si3012], and to deeply colored ultramarines. These have aluminosilicate frameworks that enclose cations but no water molecules (Fig. 16.25). Their special feature is the additional presence of anions in the hollows, e.g. Cl-, S()4, S2, or S. The two last-mentioned species are colored radical ions (green and blue, respectively) that are responsible for the brilliant colors. The best-known representative is the blue mineral lapis lazuli, Na4S (.[Al3Si3012], which is also produced industrially and serves as color pigment. 

Formerly derived from the natural mineral lapis lazuli, ultramarine blue pigments have, for more than a century, been manufactured synthetically. The materials used in the manufacture of ultramarines are china clay (a hydrated aluminosilicate), sodium carbonate, silica, sulfur and a carbonaceous reducing material such as coal tar pitch. For the manufacture of the blue pigments, the blend of ingredients is heated to a temperature of 750 800 °C over a period of 50-100 h, and the reaction... 

Second t-p. reads "The great work of the Lapis Sophorum according to Lamspring s process translated from the German by Sigismund Bacstrom, M.D. 1804"... 

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