AN EIGHTH CENTURY TREATISE ON GLASS

Kitab al-Durra al-Maknuna (The Book of the Hidden Pearl)

of Jabir ibn Hayyan (c. 721–c. 815)

ON COLOURED GLASS, ON LUSTRE GLASS, ON GEMSTONES AND PEARLS

Part Three

The Colouring of Gemstones, The Purifying and Making of Pearls And Other Useful Recipes

In Kitab al-durra al maknuna, the recipes for the lustre painting of glass are followed by twelve recipes for the colouring of gemstones and by two descriptions of the oven (tannur) used for this purpose. After this follows the last part of the treatise which contains eight recipes for the purifying of pearls, three recipes for the manufacture  of pearls, three recipes for the manufacture of glue from cheese,  mastic gum and castor oil extraction. The treatise ends with a recipe to utilise the bones of animals such as cattle and camels for producing an artificial material that can be moulded into different shapes and is light, tough and unbreakable. [1]

Colouring of Gemstones

Materials Used and the Colouring Process

The following list gives the materials used, arranged in a descending order. The most prevalent material is copper and its compounds. This is followed by alkali, slaked lime, glass and red lead:

Copper, (burnt, Verdigris, Copper scales), 9 ; Slaked lime,8; Alkali,7; Glass, 7; Lead, red (litharge), 6; Sand, red, 3; Cobalt oxide, 2; Balsam of Mecca, 3;  Pitch, 2; Borax, 1; Dragon’s blood,1;Silver, burnt, 1; Iron, scales,1; Pebbles, white,1; Sulphur, yellow,1; Mastic,1; Rosin,1; Pistacia terebinthus, resin, 1; Alum, Yemeni,1; Vitriol,1.

In a typical process the ingredients, such as burnt copper, glass, alkali, slaked lime and a resin are pulverized with vinegar or water. The gemstones are either, heated and buried in the mixture, or are placed in boxes. If boxes are used they are coated from the inside with the ingredients’ paste. The gemstones are placed inside the boxes, and the lids are closed. The boxes are then exposed to the fire of the oven (tannur) overnight and the gemstones will come out coloured.

Selected Recipes of Gemstones Colouring

Recipe 1, fol. 19a, sky colour: two and a half mithqals [2] of cobalt oxide (lazaward), two mithqals Balsam of Mecca  (resin of commiphora gileadensis - duhn al-balasan), half mithqal pitch (qitran), two mithqals pistacia  terebinthus resin (samgh al-butm). Pulverize all. Heat the gemstones and bury them in the mixture until they cool down.

Recipe 4, fol. 19a, colouring rock crystal (billaur) red: <four> mithqals dragon’s blood, one mithqal mastic, one mithqal rosin, one mithqal pitch, one mithqal balsam of Mecca  (resin of commiphora gileadensis -  duhn al-balasan). Pulverize the drugs and knead with pitch and balsam of Mecca. Heat the gemstones and bury them in the mixture. Leave them until they cool down.

Recipe 5, fol. 19a, colouring of beads sky or turquoise colour: ten dirhams glass, five dirhams slaked lime (nura), three dirhams litharge (martak), two dirhams burnt copper. These are pulverized in alkali water and the boxes and the gemstones are coated with the paste and are placed in fire overnight, and they come out as we have mentioned.

Recipe 7, fol.19b, another colouring: one part glass, one and a half parts slaked lime (nura), one part alkali, half a part burnt copper, a small amount of litharge (martak), and a small amount of red lead (isrinj). Some people throw into it verdigris (zinjar) and cobalt oxide (lazaward). And do with it as before.

Recipe 9, fol. 19b, another colouring: ten dirhams sand, three glass, three burnt copper, two slaked lime (nura), one alkali, one verdigris (zinjar). Pulverize in vinegar and coat the boxes with the paste. Kindle fire on it, and afterwards let it cool down, and they will come out nice.

Recipe 11, fol. 19b, colouring gemstones also: ten dirhams from each of vitriol (zaj) and slaked lime (nura), four dirhams alkali,  three dirhams burnt copper. Pulverize in vinegar and coat the boxes and the lids with the paste from the inside.

Recipe 12, fol. 19b, preparing the gemstones before colouring so that they can accept the colour: one part glass, and one part borax, slaked lime (nura) and Yemeni alum (shabb yamani). Put the ingredients in a pot together with the gemstones. Pour on them vinegar until they are immersed by four fingers. Cook until noon, and if the vinegar is diminished add more. Then cool down the gemstones and place them in the boxes that contain the colouring drugs.  

Description of the Oven (tannur) for the Boxes

Jabir, may God bless him, said in this respect: Build a structure similar to the oven (tannur), one dhira’ [3] by one dhira’ with a height of one dhira’ also. Make for it a banij [4] with a trough all around. The door of the fire-grate is below the banij. Mount another oven (tannur) above the banij and let it be centred evenly, and make for it a flat tray with partitions (ahjiza). In the upper oven (tannur) are shelves (in one level) and under each shelf is a <supporting > column made of clay with its lower end resting on the banij. The number of shelves is equal to the number of the boxes, either three or four. Between the shelves are spaces to allow the flames of fire to pass between the boxes and ascend over them from all sides and alternate over them. The lower oven (tannur) has < holes > [5] for the escape of smoke. Make your work according to the example [6]; and this is the end (wa al-salam).[7]

Arabic – English Glossary of Materials used in the Colouring of Gemstones

Purifying of Pearls that were discoloured

 from the Sea or from Grease

Recipe 2, fol. 20a, purifying yellow pearls whose yellowness was caused by the sea: Take the amniotic fluid, the liquid that cushions the fetus in the womb of a pregnant sheep, and put it in a bottle. Hang the pearls in this liquid for seven or nine days. Take out the pearls every three days and examine them and return them to the liquid until you reach the required purity. (al-Marrakishi says here that if the liquid becomes weak; change it.) When the pearls are cleaned and purified, put them in fresh water for five days and change the water daily, and they will come out purified.

Recipe 3, fol. 20b, another chapter on purifying yellow pearls whose yellowness is caused by sea, it is intensely yellow and is called sukkari (sugar-like): take one part white marcasite, and one part sal-ammoniac. Pulverize and combine them in a luted green earthen jug (barniyya). Place on it an alembic (anbiq) and kindle on it the fire of charcoal. Take the distillate and put it in a bottle. Hang the pearls in it for three hours, and take them out every hour and suck them with your mouth strongly. Then immerse them in cold water for two or three days and they will come out as you like, if God, the Glorious, wills.

Recipe 4, fol. 20b, another chapter on purifying yellow pearls: wash them softly in water and ashes and insert in the hole of a pearl a needle and dip it once in the milk of giant milkweed (‘ushar)[10], and take it out quickly so that it does not melt. Then wipe it softly and dip it in dog’s milk for one hour and it will come out as pure as when it came out from its shell.

Recipe 5, fol. 20b, another chapter on purifying yellow pearl: take the shells of eggs and calcine them. Knead them in dog’s milk and make them into two discs. Put the pearl between the two discs and leave it for three days. Take it out and you will find it purer than its original colour and clearer and better if God, the Glorious, wills. 

Cheese Glue

Recipe 9, fol. 22a, description of cheese glue for all duties: take old cheese that is free from fat in any amount of your liking. Cut it with a knife as thin as possible. Put it in a pot, one layer cheese and one layer salt. Immerse it for a short time with water, then take it out and wash it well with fresh water. Pour water over it and put it on a gentle fire. Be careful that water is not diminished. If it is diminished replenish it until mid-day, until you know that it is fat free. Pour out water from it, and take out the quantity that you need.  This is the same as with purified fish glue.

Put it in a luted glass vessel, and boil it in fat-free whey (dawgh دوغ) which is to be filtered before it is poured on the glue. When the glue is dissolved in it < pour it > on a flat stone mortar (sallaya) and pulverize it till you are satisfied by its coarseness or fineness.  Use it for whatever purpose you want. Know that this glue does not dissolve at all after its first application. It glues any noble stone, gypsum (qass) [11], clay, rock crystal, or glass. Wash the vessel which contains the glue before it sets, since if it sets it cannot be removed, and any object that is glued with it cannot be separated unless broken.

Artificial Pearls

Recipe 13, fol. 22b, to make pearls: take small pearls and crush them. Wash them with water and salt. Pour on them distilled rumex juice (hummad) in a clean vessel and <protect> them from dust <while warm>and whenever the rumex juice <hummad> diminishes top it up until the pearls become like dough. Then take white sea-shells and calcine them until they become like gypsum. Then take, according to your need, <washed> mercury sublimated with vitriol (zaj) and salt three times and then with salt alone between two cups until you see it like snow. Take from each one part and knead in a cup. Before this, cover your finger with a <piece> of thick cloth (qatifa) impervious to water and let it be of silk. Let the amout of rumex juice (hummad) be little if you need it. Wash your hands clean and put in your balm white and clean < cloth? >. Take from the paste an amount as much as you want, small or large, and put in its middle a thick <hair> then roll it on a silk cloth inside a cup (jam). Cover it with another. When it becomes dry knead for it dry hyoscyamus niger (banj) white and pure, and put it in its middle like a hazelnut. Take the dough of a loaf and put inside it what you have kneaded. Lay on it another loaf and put <the double loaves on the deck of the oven (tannur), and cover its head. If you know that it had been well cooked (ripened) take it out. If it is not what you like, you can follow one of two methods. One method is to bury it again inside the loaves, and put the loaves back on the deck of the oven. The second is to place it inside dough and feed it to a chicken. Lock up the chicken for two or three days, slay it and take the pearl from its gizzard. Another way is to put it inside a fish and roast it, which is better than <feeding it> to the chicken; and this is the end (wa al-salam).

  Utilizing Bones

Making a Light and Tough Material 

Recipe 15, fol. 24a, utilizing bones and making vessels from them in any <shape> you want and the material will be as pliable as lead:  Take Lychnis githago (yabruh sanami) [12] rumi one hundred dirhams, sal-ammoniac one hundred dirhams, <tincar> one hundred dirhams and asafoetida (haltit mintin) ten dirhams. Pulverize them and pour them over four ratls of wine vinegar. Place the whole over fire until half the <liquid> is gone. Take the bones of < sheep > or cows or camels. Choose the <bones > that have marrow, <meat> and sinews. Break the bones and cook them in the vinegar of old wine in a pot until they dry up, then dry them in the sun and pulverize them and sieve them through a close textured sieve. Weigh a quantity and throw it into a luted earthenware vessel. Pour on it the cooked batch of vinegar and drugs. Put the < whole> in the furnace (kur) and blow on the fire of charcoal or wood until it melts. The vinegar will dry out and the <bones> will melt like lead. If it melts and flows, take fifty dirhams of verdigris (zinjar) and five dirhams of copper scales (rusakht) and five dirhams tutia. Pulverize them and feed them to the flowing <bone mixture>, and let <the whole> flow smoothly. Then  pour the molten material into any vessel, I mean into any mould you choose, and it will come out as pliant as lead, green, without smell, and unbreakable even if you try to break it. Its greatest secret is in the high-quality of its melting. It is light having no <heavy > weight. It cannot sink at all. If you make from it mail-and-plate armours (jawasin),  helmets (bid) and shields (daraq), they cannot be cut by iron. And this is the end (wa al-salam)

The reason for choosing marrow bones is that they are more moist, and the more moist the bones are the stronger will be the < material >. The cause of this is that the <bones> are cold and dry originally. If their dryness is too much their interior will be tender and they will be easily broken because of this. If moisture flows in them, which is the marrow, this moisture will be in equilibrium with dryness and with coldness  if the material becomes slightly warm the dryness will depend in its entirety on that moisture which is inherent and latent in it and which hardens it and makes it <resistant to breakage>.  When fire touches its moisture it becomes malleable. This is because fire introduces dryness and dryness is thus augmented. This necessarily prompts moisture to come into action and thus melting takes place quickly; if God, the Glorious, wills. We shall discuss the manufacture of this <material> and its different kinds in a special book devoted to it, if God the Glorious, wills, and this is the end (wa al-salam)

May God send his blessings and peace on our master Muhammad.

This is the end of Kitab al-durra al-maknuna.                                                                                         

Arabic-English Glossary of Materials used in Pearl Purifying, Pearl Making, Glues and Bones Utilization