Sunday, August 22, 2010

On Mines and Mining - Part Five

The Finale! Previous posts are as follows:

Part One: Mining and Smelting
Part Two: Alabaster to Corundum
Part Three: Diamond to Lodestone
Part Four: Marble to Rhodochrosite


Natron (5 sp / lb): Art, Preservation
Salt (5 gp / lb): Alchemy, Cooking

Salt occurs as a white, pink or reddish mineral in rock salt form. Rock salt occurs in vast beds of sedimentary minerals resulting from the drying of enclosed lakes and seas. These salt beds may by up to 350 meters thick and cover many square miles. Salt is also extracted from sea water.

Salt can be extracted from rock salt deposits by mining it. This was traditionally a very dangerous profession, and thus left to slaves and convicts. The salt occurs in the form of irregular salt domes, and may be transparent, white, pink, reddish or red in alternating bands. Some salt mines still in operation today are very ancient, including famous mines in the Punjab and Poland. These mines cover many square miles, run up to 10 levels deep, and have hundreds of miles of passages and thousands of chambers. In other words, they would make perfect dungeons.

Salt can also be collected from salt water from the sea or from brine springs. When extracted from water, the salt is either evaporated from the water using salt pans (pots made from a crude ceramic material called briquetage) or by boiling it down over a fire. Even when boiling is used, the brine is usually allowed to evaporate in salterns in order to concentrate it before the boiling occurs.

Salt is a useful material on its own, primarily as a food additive and an alchemical ingredient. At some points in time it was almost as valuable as gold. Alchemists can make spirit of salt, or hydrochloric acid, by mixing salt with vitriol (sulfuric acid). Spirit of salt was mixed with aqua fortis (see Urine) to produce aqua regia, the gold dissolving acid. Alchemists also used salt to produce sal mirabilis, or miraculous salt, a popular laxative.

Another product of dry sea beds is natron. Natron was used as a grease-cutting cleaning agent, a mouthwash, and tooth paste. When blended with olive oil, it made soap. Natron was an ingredient in antiseptics and it was used to dry and preserve fish and meat, kill insects, make leather and bleach clothing. The Egyptians used it in the mummi-fication process because it absorbs water. When added to castor oil, it made a smokeless fuel, allowing artists to pain in tombs without staining them with soot. The Romans combined natron with sand and lime in their glass and ceramic production, and it was used as a flux in soldering precious metals and as an ingredient in blue paint.

Sandstone (8 sp / lb): Architecture

Sandstone is a sedimentary rock composed of sand-sized minerals. Most is comprised of quartz and feldspar, the most common minerals in the Earth’s crust. Sandstone is usually colored tan, brown, yellow, red, gray and white. It is a common building material because it is easy to work and often resistant to weathering.

Serpentine (1 gp / lb): Architecture, Art

Serpentine is a group of many different minerals. The Romans called them “serpent rock”. They come in colors ranging from white to grey, yellow to green, brown to black and they are usually splotchy or veined. Serpentine is plentiful in sea beds. In the soil, it is toxic to plant life, and thus deposits often underlie strips of grassland in wooded areas. Serpentine marble (lizardite) ranges from red to green and weathers very well. Serpentine is a common stone in hardcarving. It can be carved into art objects or used as an architectural facing.

Silver (100 sp / lb): Art, Coins, Equipment

Silver, or argentum, is a whitish metal that is harder than gold, but still easily worked. This made it an excellent material for making coins, and in fact most coins through history were minted from silver. There are three main sources of silver: Quartz, galena and acanthite. For more information on quartz, see the entry for Gold & Quartz. For information on galena, see the entry for Lead. Acanthite is a blackish-grey mineral with a metallic luster.

Silver is most often used to make coins. Historically, silver coins were far more common than gold and copper (or bronze, brass, billon or potin) coins. In fantasy games, silver is also used on weapons, probably in the form of silver plate, because of its effect on lycanthropes. Silvering a weapon would probably involve the use of mercury, and would be performed by an alchemist rather than a smith.

Lunar Caustic, or lapis infernalis, was made by dissolving silver in aqua fortis and evaporating the substance. Sticks of lunar caustic were used in surgery because of its antiseptic properties. It blackens the hands. Argentum fulminans, or fulminating silver, is a silver compound that explodes readily, though the charge is fairly harmless in small amounts.

In mythology and folklore, silver is associated with the moon, thus lycanthrope’s vulnerability to silver.

Slate (5 cp / lb): Architecture

Slate is a grey stone formed from shale. The most common use for the stone is roof shingles, though high quality slate can be used for grave markers and other monuments.

Soapstone (1 cp / lb): Art

Soapstone is rock composed of talc and rich in magnesium. Soapstone has been a medium for carving for thousands of years. Native Americans used it to create bowls, cooking slabs and smoking pipes, the Indians for temple carvings and the Chinese for official seals. It is highly heat resistant, making it a good material for cooking slabs, seals that are to be dipped in hot wax and as a mold for soft metals.

Spinel: Medium Gem

Spinel is a class of minerals found in gemstone bearing gravel, limestone and marble. Spinels range from blue to mauve or dark green, brown or black in color.

Black Powder (3 gp / lb): Equipment (Guns)
Sulfur (1 sp / lb): Alchemy, Laundry, Medicine
Vitriol (10 gp / vial): Acid

Sulfur is a soft, yellow mineral that can be found near volcanoes and hot springs and in salt domes. It can also be extracted from pyrite (iron + sulfur), cinnabar (mercury + sulfur), galena (lead + sulfur), sphalerite (zinc + sulfur), stibnite (antimony + sulfur) and the sulfates, gypsum, alunite and barite.

Sulfur is extracted by stacking deposits in brick kilns built on sloping hillsides, making sure to leave airspace between them. Powdered sulfur is then placed on top of these piles and ignited. As the elemental sulfur burns, the heat melts the sulfur in the deposits, causing molten sulfur to flow down the hillside. It is then collected in wooden buckets.

Sulfur was used by the Egyptians to treat granular eyelids, and the Greeks used it for fumigation and bleaching cloth. Sulfur was also used, along with phosphorus, by Robert Boyle in a forerunner to modern matches. Sulfur is odorless. The odors associated with it come from hydrogen sulfide in rotten eggs and sulfur dioxide in burnt matches.

Alchemists could turn sulfur into a powerful acid called vitriol. Vitriol was, in fact, sulfuric acid. It was made by burning sulfur into sulfur dioxide, and then converting the sulfur dioxide into pure sulfuric acid.

The colors of Jupiter’s moon Io are from various forms of sulfur. The planet probably smells of brimstone, and could be an excellent haunt for demons and devils.

Clay (5 cp / lb): Art

Terracotta, from the Italian for “baked earth”, is a clay-based ceramic. Terracotta usually has a reddish-orange color. Terracotta could be glazed or unglazed. It could be used to make pottery, figurines, bricks and roof shingles. Perhaps the most famous use of terracotta was in the creation of Chinese Emperor Qin Shi-Huang’s terracotta army. Virtually all cultures made use of terracotta, from China to India to Greece and Western Africa. Terracotta could be dried in the sun or baked in kilns.

Tin (3 gp / lb): Alloys, Equipment

Tin, or stannum, is a silvery metal that is primarily found in an ore called casserite. Pure tin deposits are sometimes found near river and stream flows. Miners harvest this tin by digging a trench at the bottom of a deposit, loosening the gravel with a pick, and then running water over the gravel to remove unwanted material. This process creates gullies. Casserite occurs in quartz deposits. It is a black to reddish brown to yellow crystalline mineral. It is found with tourmaline, topaz and arsenopyrite (q.v.).

Tin was mostly used in the form of bronze or pewter. Bronze is an alloy of tin and copper (see Copper above). Pewter is an alloy of tin and lead (85:15) that might also contain portions of antimony or copper.

Tin ingot currency (see below), with each ingot weighing one pound, was used in Indo-china and the Malay Peninsula during the 14th and 15th century.

Alchemists created “butter of tin”, or tin chloride, which was used in the dyeing industry to fix colors.

Topaz: Medium Gem

Topaz is a gem that occurs with granite or rhyolite lava flows. Pure topaz is colorless, but tinted wine, yellow, pale grey, reddish-orange or blue-brown from impurities. Precious topaz is orange and imperial topaz is yellow, pink or pink-orange. Blue topaz is the rarest. Folklore holds that topaz wards away evil spirits.

Tourmaline: Medium Gem

Tourmaline is a semi-precious stone found compounded with such elements as aluminum, iron, magnesium, sodium, lithium and potassium. It occurs with granite, marble and schist. There are several varieties of the gem. About 95% of all tourmalines are schorls, and colored bluish to brownish to black schorl. Dravite is a dark yellow to brownish-black, rubellite is rose or pink, indicolite is light blue to bluish-green, verdelite is green and achronite is a colorless tourmaline.

Turquoise: Minor Gem

Turquoise is blue-green mineral. It is a hydrous phosphate of aluminum and copper. Even the best turquoise is only a bit harder than glass. It forms from the action of acidic solutions on pre-existing minerals during weathering, often from such minerals as malachite and feldspar. Turquoise is often a by-product of copper mines. Turquoise has been valued as a precious stone for thousands of years. It was used by the ancient Aztecs, Chinese, Egyptians, Mesopotamians and Persians, for whom it was the national stone. The name derives from the French for a product derived from Persia imported through Turkey. It did not become a common ornamental stone in Europe until the 14th century. Common belief held that the stone had prophylactic qualities, and would change color to indicate the health of its owner. It was also supposed to aid horses.

Aqua Fortis (50 gp / vial): Acid
Black Powder (3 gp / lb): Equipment (Guns)
Saltpeter (2 gp / lb): Alchemy

Urine is not a mineral, but it contains minerals and it was an important material for Medieval industry. It was used as a source for both phosphorus (q.v.) and saltpeter, or potassium nitrate. Saltpeter is Latin for “stone salt”, and it was a critical ingredient in black powder and slow matches. Saltpeter was obtained by mixing manure with either mortar or wood ashes, common earth and straw into a compost heap 5 feet high by 5 feet wide by 15 feet wide. The heap was covered to protect it from the weather and kept moist with urine. This leached the water from the heap after one year, with the remaining liquid being mixed with wood ashes to produce saltpeter. The saltpeter crystals are added to sulfur and charcoal to produce black powder.

From saltpeter, the alchemist can produce aqua fortis, or strong water. Aqua fortis is nitric acid, a highly corrosive and toxic substance. Aqua fortis was used as a solvent to dissolve silver and most other metals, with the exception of gold and platinum. It was prepared by mixing sand, alum or vitriol with saltpeter and then distilling it by a hot fire. The gas that is produced condenses into aqua fortis. Refiners used this acid to separate silver from gold and copper, to mosaic workers for staining and coloring wood, and to other artists for coloring bone and ivory a fine purple color. Book binders used it to produce a marble effect on leather. Lapidaries use it to separate diamonds from metalline powders and to etch copper and brass. When mixed with oil of vitriol, it was used to stain canes with a tortoise shell effect.

Alchemists mixed aqua fortis with spirit of salt to create aqua regia, the gold dissolving acid and an important step in the creation of the philosopher’s stone.

Zinc (7 gp / lb): Alloys

Zinc is a grey metal that is found in deposits of sphalerite. Sphalerite, which is also called zincblende, black-jack, and mock lead, is a yellow, brown or grey mineral.

Zinc is smelted by roasting in an oven. The zinc is placed in a clay retort shaped like a cylinder resting on a funnel. The retort is also packed with dolemite and a fuel like cow dung. The retort is then placed vertically into a furnace, which causes the zinc to become a vapor that condenses in the clay funnel and drips into a collection vessel. Such a furnace can separate 450 pounds of zinc in a day, producing sulfuric acid as a by-product.

Zinc is primarily used as an alloy with copper in brass. Flower of zinc, an alchemical compound also called zinc oxide, was used as a salve for the eyes, skin conditions and open wounds. It is still used in baby powder and creams that prevent or fight rash. The Romans used flower of zinc in paints and to make brass.

Hyacinth: Medium Gem
Jacinth: Medium Gem
Jargoon: Medium Gem
Zircon: Medium Gem

Zircons occur in many kinds of rocks, but mostly granite. Zircons can be black, brown, hazel, pink, red, yellow or colorless. Light colored zircons are called jargoons, a corruption of the Persian zargun, or “golden colored”. Red zircons are called jacinths, and yellow zircons hyacinths.

Zircons were believed to decorate the lost city of Iram and the hilt of Excalibur. In the Roland cycles, Ganelon gave his wife Bramimunde two golden necklaces inlaid with jacinths and amethysts. According to the Book of Enoch, there is a mountain of jacinth in Hell. Jacinth was believed to be a good luck stone for travelers. It also wards off plague and protects one from fire.

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