Thursday, August 12, 2010

On Mines and Mining - Part Three

Entries D-L. Click for Part One and Part Two.

Diamond; Major Gem

Diamonds are the hardest known minerals. Perfect diamonds are clear and colorless, while other diamonds contain impurities that lend them a tint. These colors, in order of their rarity, are yellow, brown, blue, green, black, translucent white, pink, violet, orange, purple and red. Diamonds are the product of deep, volcanic eruptions and thus appear in volcanic areas, often in river deposits. Diamonds can also be formed by meteor impacts. The name is derived from the Greek for “un-breakable”. Indians venerated them as religious icons. The undead are vulnerable to diamonds.

Feldspar, Moonstone and Sunstone
Moonstone; Minor Gem
Sunstone; Medium Gem

Feldspar is an igneous rock formed from magma flows. It is one of the most common rocks in the Earth’s crust. The name derives from the German for “field” and “a rock that does not contain ore”. It is a common ingredient in the production of ceramics and it is used as an abrasive.

There are two forms of feldspar that are considered precious stones. Moonstone is a feldspar with a pearly, luminescent luster. Moonstones were believed to cause lycanthropy. Sunstones are a transparent, reddish feldspar with a spangled appearance. Sunstone is believed to ward spells, evil spirits and poison.

FlintFlint (7 cp / lb); Architecture, Equipment

Flint has been mined since prehistoric times. It is a form of quartz known for its hardness. Flint occurs as nodules and masses in sedimentary rocks such as chalk and limestone. Inside the nodule, it is a dark grey, black, white, green or brown in color, and usually glossy. When struck, flint splits into sharp flakes or blades. This process is called knapping, and was used during the stone age to made tools and weapons. When struck against steel, flint produces sparks. This alone makes it useful to adventurers. Because of its ability to create sparks, flint was used in flintlock firearms. Flint was also used a building material. Nodules of flint will explode if heated by fire.

Garnet; Medium Gem

Garnet is a group of minerals that has been used since the Bronze Age as gemstones and abrasives. Among their number are carbuncles (almandine), a deep red stone that occurs in mica schists. Carbuncle was believed to have been present in the Garden of Evil. Pyrope (“fire eyed) is a transparent garnet colored deep red to nearly black. Uvarovite is a bright green garnet that occurs in crystalline marbles and schists, but it too small to facet. Carbuncles are supposed to give one the keen sight of a dragon.

Faience (5 gp / lb); Art
Glass (3 sp / lb); Art

Glass is made from silica and other compounds, typically soda, lime, lead and even pitchblende. The impurities might make the glass easier to work, glossier or tinted. Naturally occurring glass, like obsidian, were used by primitive people to make tools and weapons. The first true glass was made in the Middle East. The earliest glass products are beads, but by the Bronze Age people were making colored glass ingots and vessels. By the Middle Ages, most of the glass items we are used to today, such as windows, dining ware and mirrors, were in production.

Faience is an early ceramic invented by the Egyptians. Faience contains no clay. Rather, it is composed of crushed quartz or sand, with small amounts of lime and other ingredients. In the early days, it was given a blue-green glaze and used as a substitute for precious stones of that color, such as turquoise or lapis lazuli.

Electrum (50 gp / lb); Art, Coins
Gold (100 gp / lb); Art, Coins

Gold, or aurum, is a shiny, yellow mineral that has been valued by humans since ancient times. It is found in quartz deposits, usually with silver, sometimes in the form of electrum. The Romans uncovered gold deposits by unleashing pent up water to wash away the top soil. The quartz was then mined with picks and shovels, crushed, and washed in placers to separate the gold.

Gold is inert and malleable, making it an excellent material for coins and other art objects. Gold was alloyed with copper to create orichalcum and hepatizon. In quartz deposits, It was found as a natural alloy with silver called electrum. Electrum is harder and more durable than gold, so it was used as an early coinage. Unfortunately, the difficulty in determining the exact ratio of gold to silver in electrum meant it was impossible to determine the true value of an electrum coin. For this reason, silver soon replaced electrum as the metal of choice for coinage. Most electrum is 75% gold and 25% silver and copper. For fantasy coinage, it is simple enough to assign electrum coins a value between gold and silver.

Gold was associated with the Sun. It was believed to be the perfect, most noble metal because it is inert and only dissolved in aqua regia. The secret of turning base metals into gold was not merely a quest for wealth. Rather, the mystic alchemist was attempting to reach perfect spiritual purity, transforming his mortal form into a divine form.

GraniteGranite (3 gp / lb); Architecture

Granite is an igneous rock formed from magma. It has a coarse texture and can be pink to dark grey to black. Outcrops of granite tend to form tors or rounded massifs, and sometimes occur as round depressions surrounded by hills. The name is derived from the Latin for “crystalline rock”. Granite is hard, tough and heavy, and thus favored as a building material. Some of the pyramids were built of granite blocks, or a combination of granite and limestone.

Hematite; Minor Gem
Ochre (6 sp / oz); Pigment
Tomb Dust (100 gp / lb); Trap

Hematite is black to reddish brown to red mineral found in bodies of water or near volcanoes. It usually occurs in banded iron deposits, which are found in primordial sedimentary rocks, usually with thin bands of shale and chert. Hematite is an iron-bearing ore (see Iron), but has many uses in its own right.

Hematite gives ochre clay its color. Ochre was a common cosmetic in ancient and medieval times, being used by Egyptian women to color their lips and Pict warriors to color their bodies for war. In powdered form, it is used as a trap in tombs. The powdered hematite is scattered thickly on the floor to be stirred up by tomb robbers. Once airborne, it irritates the skin, eyes and nose, eventually causing siderosis, a lung disease. Hematite is used as a gemstone in jewelry, especially as an engraved gem.

Hematite is believed to have the power to heal wounds and can aid fighters in combat. It is also supposed to be good for ailments of the blood.

Copperas (5 sp / lb); Equipment (Ink)
Iron (8 sp / lb); Equipment
Iron Pyrite (2 sp / oz); Equipment (Guns)
Steel (5 gp / lb); Equipment

Iron, or ferrum, occurs in the mineral iron pyrite and in banded iron deposits. Iron pyrite, also called brazzle or fool’s gold, looks vaguely like gold ore. Iron pyrite creates sparks when struck with steel, and is thus useful for starting fires and igniting guns. Banded iron deposits are found in primordial sedimentary rocks with thin layers of shale and chert. Banded iron deposits also contain hematite and lodestone.

Iron was first gathered by humans from meteors. This meteoric iron had a high nickel content, and was used to make tools and weapons. Iron was harder and more durable than bronze, and thus highly valued. The Hittites traded silver for it at 40 times the weight of the iron. Bog iron was used by the Celts and Vikings, and in Colonial America. Bog iron occurs where iron is eroded from stone by a river and then settles in a bog.

Iron is smelted from iron pyrite using bloomeries, blast furnaces and fineries. Most processes create either wrought iron or bar iron, which can be used to make cast iron objects. There are various methods for refining iron into steel by removing carbon impurity.

Iron pyrite is used in wheel-lock firearms. It was also used to make copperas (see below). This was done by heaping it up and allowing it to weather, the acidic runoff being boiled with iron to produce copperas. Copperas, in turn, was an ingredient in vitriol, or sulfuric acid (see Sulfur).

Alchemists used iron in the production of copperas, which they nicknamed the green lion. Copperas is iron-sulphate, a blue-green powder. It was used in the manufacture of gall iron ink and in wool dyeing. Gall iron ink was the standard writing ink of Medieval Europe. It was made by mixing copperas with gallotannic acid and gum arabic. Gallotannic acid is extracted from oak galls and fermented. Gum arabic is the sap of the acacia tree. The result of the mixture was a pale grey solution which darkens to a purple-black color when put on vellum or paper. It cannot be erased or washed away, only scraped, making it a good ink to use in spellbooks and important documents. Gall iron ink must be stored in a stoppered bottle and becomes unusable after a time. Its high acid content eventually destroys the paper and vellum it is put on.

Folklore often held that fairy-folk had an aversion to iron, or were in fact harmed by it. A Referee might want to allow iron or steel weapons to do +1d6 points of damage to fairy creatures, and maybe +1 damage to elves. This would leave elves using bronze weapons.

Jade; Minor Gem, Muscial Skill

Jade is actually two metamorphic stones called nephrite and jadeite. Nephrite is white or a variety of greens, while jadeite might be blue, lavender, mauve, pink or emerald green. Translucent green jade is the most valuable.

Jade has been carved since prehistoric times. It has the same toughness as quartz and has been carved into beads, buttons, axe heads, knives and all manner of art objects. Jade is usually worked with quartz or garnet sand and polished with bamboo or ground jade.

Jade’s name is derived from the Spanish for “loin stone”, as it was reputed to cure ailments of the loins and kidneys. It was the imperial stone of China and considered more valuable than gold or silver. It was the favored medium for carving scholarly items and opium pipes, because inhaling the fumes through jade would insure long life.

Jet; Minor Gem

Jet is a black or dark brown mineraloid that forms from decaying wood under extreme pressure. In essence, jet is a precious form of coal. Jet has been used in jewelry since 17,000 BC. Hard jet is the result of carbon compression and salt water, while soft jet results from fresh water.

Lapis Lazuli
Lapis Lazuli; Minor Gem

Lapis lazuli is a rock, not a mineral. It occurs in limestone deposits in Badakhshan province in Afghanistan. The rock has been mined, and valued, for 6,000 years. Lapis lazuli is made into jewelry, carvings, boxes, mosaics, ornaments and vases and is also used to clad the walls and columns of palaces and temples. Lapis lazuli is also ground into a powder to make ultramarine pigment for painting. It was used by the Assyrians and Babylonians for making seals and favored by the Egyptians for making amulets.

Lead (1 gp / lb); Alloy, Coins, Forgeries

Lead, or plumbum, is a bluish-grey metal that is very soft. It tarnishes very quickly, taking on a dark grey color. Lead is found in a mineral called galena. Galena is a silver-grey mineral that contains lead, silver, sulfur and arsenic.

Galena was initially mined from surface deposits using the fire-setting technique. It was then followed into veins that usually followed vertical fissures. Surface deposits are found in blighted areas, as lead is poisonous.

Lead was originally smelted from galena in boles, large fires built on a hill that used wind to stoke the flames. This required two days of strong wind and left a large heap of ore. Later, water mills powered bellows that stoked furnaces fueled by “white coal” (dried branches). The ore would be washed and smashed into bits and then smelted in these furnaces and cast into ingots. By-products of this smelting included silver and arsenic.

Galena was used in its own right as kohl, an Egyptian cosmetic for the eyes that was used to reduce the glare of the desert sun and to repel flies. Kohl was also used into Elizabethan times to give the skin a noble pallor.

Lead was most famously used by the Romans to cast pipes for their water and sewage systems. The Romans also used it to make terrerae, tokens distributed by the emperor that entitled the holder to food or money, and as a food preservative. The Chinese used lead to mint coins. Lead is part of the copper alloy called potin, which was also used to make coins. Geishas in Japan used lead carbonate for face-whitening make-up. Lead was also used in forgeries by plating it with gold.

Alchemists once made “sugar of lead”, or lead acetate. The substance has a sweet taste, and was used as a reagent to make other lead compounds, a fixitive for many dyes and as a sugar substitute. The Romans would produce it by boiling grape juice in lead pots. This would yield a sugar syrup called defrutum, which was further concentrated into sapa. The syrups were used to sweeten wine and to sweeten and preserve fruits. One possible result of using this syrup is, of course, lead poisoning.

Limestone (1 sp / lb); Architecture
Quicklime (2 sp / lb); Alchemy
Travertine (2 gp / lb); Architecture

Limestone is a sedimentary rock comprised of calcite with measures of chert, flint, clay, silt and sand. Limestone makes up about 10% of the world’s sedimentary rocks, and is a common building material. The Great Pyramid at Giza is made entirely of limestone blocks. The English used a variety called beer stone in their churches. Crushed, lime-stone makes a solid base for road construction. Limestone can also be roasted down to create quicklime. The English once used quicklime as a weapon against a French fleet, throwing it in the eyes of their opponents. Quicklime was also an ingredient in Greek Fire, for when combined with water it increases its temperature to above 150-degrees and ignites the fuel.

Lodestone (25 gp); Magnet

Lodestone, or magnetite, is the most magnetic of the minerals. It can be found in the form of black sand on beaches and in banded iron deposits with hematite (q.v.) and iron (q.v.). Lodestones are black minerals.


  1. Have I mentioned that I like your stuff ? well, I do. So there !

    I'm going to need to get the download of NOD when I'm not behind a firewall.

  2. Thank you kindly, Sir! I enjoy your blog as well.

  3. This is far more interesting than it has any right to be.

  4. Thanks! It all came from the first time I had to describe a random mine and I realized I had no idea what I was talking about. Once I got into the (light) research, I found it pretty fascinating.


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