On Minerals

Pearl original: "Margarita" The Pearl is a stone found in dark shellfish; the best ones come from India. Many are also found in the British Sea, which is now called the English Sea, and toward Flanders and Germany; indeed, I once had ten on my table at one time which I found while eating oysters. Young shells contain better pearls; some of them are perforated, while others are whole and solid in color, appearing as if a small light were penetrating through a mass of white, and therefore they shine despite being white. It is also said that during thunder, the oysters vomit them up as if by miscarriage; for this reason, they are found in the river Moselle and certain rivers of France. They are effective against heart trouble original: "cardiacam" and fainting original: "sincopim"; they are also useful against the flow of blood, the "lienteric" flux a form of diarrhea where food passes undigested, and against common diarrhea.

Median Stone original: "Medus" The Median Stone is so named because it comes from the region of the Medes an ancient Iranian people, where many are found. There are two species of this: one black, the other green. They say its power works against chronic gout original: "podagram", blindness of the eyes, and kidney disease original: "nefreticam"; they also say it refreshes those who are tired, weary, and weak. However, they report that if fragments of the black variety are dissolved in hot water and someone washes with that water, they will suffer the peeling of their skin, and if they drink from it, they will perish by vomiting.

Malachite original: "Melochites" Malachite, which some call "melonites," is an Arabian stone of a thick green color; it is not translucent like an emerald, and it is soft. It is said to have the power to protect the person carrying it from harmful accidents, and likewise to protect the cradles of infants.

Memphite Stone original: "Memphites" The Memphite Stone is named after the city of Memphis in Egypt. It is said to be as hot as fire in its properties; when crushed and mixed with water, it is given as a drink to those who are to be cauterized or cut, because it induces insensibility so that they do not feel the torture an early reference to surgical anesthesia.

Magnesia Magnesia, which some call "magnosia," is a black stone frequently used by glassmakers; this stone melts and flows in a large and powerful fire, and not otherwise; when mixed with glass, it brings the substance of the glass to a state of purity This likely refers to manganese dioxide, known as "glassmaker's soap" for its ability to remove green tints from glass.

Marcasite original: "Marcasita" Marcasite, or "marchasida" as some say, is a stone in substance that has many species, for it takes on the color of various metals; thus there is silver marcasite, gold marcasite, and so on for others. However, the metal that colors it does not melt away from it but evaporates in the fire, leaving behind useless ash; this stone is well known among the alchemists and is found in many places.

Chapter 12. Concerning stones beginning with the 13th letter, which is M.

Nitre original: "Nitrum" Nitre also pertains to the hardening of stone; it is somewhat pale and transparent. Its power is proven to dissolve and attract; it is effective against jaundice original: "ictericiam" and belongs to the genus of salts.

Michomar Michomar is the same as Alabaster, which is a type of marble; however, because its power is wonderful, it is placed among the precious stones. It has been proven through experience that by its coldness it preserves aromatic

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ointments. For this reason, the ancients made ointment jars original: "pytrides" from this stone. By its coldness, it also preserves the bodies of the dead from foul odors; thus, ancient monuments and mausoleums are found made of this stone. It is a shining white. They also say it grants victory and preserves friendship. There are also some who say there is a certain stone called Nufe, of the genus of "toad-stones" original: "bufonibus", and it is found in many toads. There are two kinds: one is whitish, as if milk had entered blood and overcome it, and therefore they say dark veins of blood appear in it; the other is black, and sometimes a toad with its feet spread front and back is depicted upon it. They also say that if both are enclosed together in the presence of poison, they will burn the hand of the one touching them. The proof of this stone, they say, is that if it is shown to a living toad, the toad will rise up against it and touch it if it can. It is also said that the whitish variety changes its appearance in the presence of poison.

Chapter 13. Concerning stones beginning with the 14th letter, which is O.

Onyx Onyx is considered a gem of black color; the best kind is found to be black varied with white veins. It comes from Media and Arabia. There are five different varieties found due to the diversity of the veins and colors. They say that when hung from the neck or worn on the finger, it provokes sadness and fears, and terrible visions in sleep; it is reported to multiply sorrows and quarrels. However, they say it increases saliva in children. If a Sard stone Sardonyx is present, the onyx is bound and hung so as to prevent harm; all these things happen because it has the power to stir up "melancholy" the humor associated with black bile and sadness, especially in the head, and from its movement and vapor all these effects proceed. Some say Onycha or Onychulus are the same thing, which is likely, or that it is some species of it; its color is not black except in some parts, but it has the color of a human fingernail The name 'Onyx' comes from the Greek word for fingernail, as we said above. But under the name of onyx, many colors are found—white, black, and reddish—all of which are formed in a substance that expresses the likeness of a human nail. They also say it is generated from the hardened tear of a tree called the "Onica"; they claim this is why it is fragrant in fire. They say this is also the reason why it is found more frequently than others carved with wonderful images, because the "tear" is soft and easily shaped at the beginning, and the picture is retained when it hardens into stone. They say this stone can enter the eye without being felt, which is wonderful. But I have seen a sapphire enter the eye, and a "cock-stone" original: "lapidem galli", and another whose name I do not know, without injury to the eye; for when polished and thin, it does not hurt the eye unless it touches the sharp point or the sensitive pupil near the opening of the uvea.

Opal original: "Obtalmos" Opal is a stone named after "ophthalmia" eye inflammation; its color is not specifically named, perhaps because it consists of many varying colors. It is said to be effective for the wearer against all bad diseases of the eyes; however, it is said to blind the sight of bystanders suggesting a legendary power of invisibility...