|
highly praised by Arab poets.
The coral or coralline (Comilium rubrum Lam) is classified and
defined in pharmaceutical compendia, lexicons and formularies. The various species of corallia are hard calcareous skeletons of marine polyps, reefs and atolls. They multiply in tropical seas such as the Red Sea which abounds in a great variety of them. They are renowned since antiquity for their unusual beauty, and superb majestic patterns. If bleached by vinegar, they become shiny and luminous. Lapis lazuli, known as azure blue, is generally an opaque semiprecious stone referred to in pre- and Islamic Arabic lapidary literature.
This and the malachite were both mentioned in Pedanius Dioscorides' Materia Mcdica (Book V, 89, completed about C.E. 63) and used by alchemists for the transmutation of the philosophers' stone, and was known and used in ancient Egypt, Mesopotamia and India. The hematite is the crystallized blackish iron oxide (in modern
jargon, Fe2 O3) or ferric oxide known in many industries since ancient times. However, jade refers to two rock-forming minerals similar in appearance but practically unrelated species. (1) The jadeite constituting the pyroxenes, that is, the sodium aluminium silicate in a white and emerald green and other colours. It is characterized by its superb types of fine-quality workmanship and carvings. It is highly priced so that a one-inch carved original jade is worth a fortune, due to its toughness, tenacity, the skill of proficient artisans and carving techniques and its extraordinary characteristics. (2) The nephrite, called amphipoles, is calcium magnesium silicate ranging from the white and the green to the blackish in colour. It measures 6.5 on the hardness scale, but it stands a great amount of abuse and is not easy to break or scratch. It has been known and appreciated in China and other countries of the Far East from the first millennium or earlier until the present. Glass was discovered and received wide publicity since the third
century B.C. in Egypt, Lebanon and Syria. It was manufactured by mixing sands, salts and other impurities, such as lead, lime, sodium and magnesium compounds, melted over ovens or strong fires for long time. Glassy matters were also dug, melted, fired, purified and solidified from deposits, the earth's crust, and over alkaline lakes. The manufactured glass also turns into a great variety of coloured
specimens of superb works of art as explained by the author. Such glassware and pottery were described then, and are presently preserved or displayed in museum exhibits and galleries. Great industries, therefore, arose throughout the Arab-Islamic world. When batches or individual wares were broken or ruined, they were crushed and powdered, then solved, remade and remodelled, and fired again. Enamelling and glazing can be applied, and after firing, they become ready for better |
||
|
|
||
|
257
|
||
|
|
||