Making gems. Part one: fish black

We’re back! Just for a one-off mini-series, though. Probably.

In the previous series, we explored recipes for imitating gold, silver, coral, and pearl from the 16th-century “Nectar Mine Light on Mercury” (Rasaprakāśasudhākara). As you may remember, we found some parallel recipes for imitation coral in another, older alchemical work, the “Jewel Mine of Mercury” (Rasaratnākara). The recipes from the Jewel Mine filled in some of the gaps of the Nectar Mine Light’s recipe, though they also raised some new questions with their variations.

The relevant formulations were all found in chapter nineteen of the Jewel Mine’s third book, the “doctrine section” (vādakhaṇḍa), which gives a series of recipes for producing gems. A veritable jewel mine (haha, see what I did there?)....

Apart from the recipes for making pearls and coral, the chapter features recipes for rubies (padmarāga), sapphires (indranīla), emeralds (marakata), garnets (gomeda), topazes (puṣparāga), and blue sapphires (nīlamāṇikya). It seems that these recipes are unique to the Jewel Mine, or at least that it is the only alchemical work to feature them. All these recipes, excepting those for coral and pearls, are based on a particular ingredient: fish collyrium/ fish black (matsyakajjala), the recipe for which is found right at the beginning of the chapter (Rasaratnākara vādakhaṇḍa 19. 2-5ab). Here it is:

चतुर्गुणेन तोयेन लाक्षां पिष्ट्वा तु तद्द्रवैः ।

वस्त्रपूतं शतपलं गृह्य मृद्भाण्डगं पचेत् ॥२॥

मृद्वग्निना पादशेषं जातं यावच्च तस्य वै ।

क्षिपेत्पलं पलं चूर्णं सर्जितंकणलोध्रकम् ॥३॥

किंचित्पच्यात्ततः शीतं काचकूप्यां सुरक्षयेत् ।

स्थूलमत्स्यत्वचं पच्याद्दिवारात्रं जलेन तत ॥४॥

घनीभूतं समुतार्य ख्यातो ऽयं मत्स्यकज्जलम् ।

Rub lac with four times its amount of water;

take 4,8 litres of this liquid, filtered through a cloth,

and boil it in an earthen vessel on low heat, until a fourth of it remains.

Add 48 g each of powdered natron, borax, and lodhra (Symplocos racemosa Roxb.).

Heat it a bit. Then, once it has cooled down, fill it into a glass bottle.

Cook the skin of a fat fish for a day and night with this water.

When it has thickened, remove it. This is known as “fish black”.

So, our ingredients were

1. lac

2. water

3. natron

4. borax

5. lodhra

6. fish skin

Among these, lac (Sanskrit: lākṣā) is perhaps the most interesting ingredient. It is the resinous secretion of lac insects, of which the most commonly cultivated is Kerria lacca. Farmers cultivate Kerria lacca on various host plants. In India, these are typically either Dhak, Ber, or Kusum trees. The latter is considered to produce the best yield and quality.

To cultivate lac, a stick with Kerria Lacca eggs is tied to the tree that is to be infested. Once the lac insects hatch, they colonize the branches of the host tree and secrete a resinous pigment on them. This resin, called sticklac, is harvested – usually by cutting off the whole branch and then scraping the lac from it.

There are two main lac products: dye, and shellac. The latter is used as a wood finish, for lacquer ware, and ornaments. Shellac is highly processed, with all insect parts removed. However, it is the insects that carry the dye, so if lac is processed to obtain dye, they are kept in the resin. The colorant is extracted from the resin through a water extraction process. The more insects, the redder the dye.

Here is a video (not ours) on lac cultivation, harvesting and processing to make shellac.

And a rather lovely video (also not ours) on how to extract the dye:

And here is an article written in 1804 by Charles Hatchett that describes lac and its properties.

As it happens, Andrew had a few bags of lac floating around. However, we hadn’t really taken in the difference between the different lac products. He had seed lac and button lac, which is lac that has already gone through a first purification process, in which most of the insect parts, and hence the dye, have been removed. One of the bags, however, contained stick lac from Peepal tree. The recipe in the Jewel Mine just states that lac is used, so we assume that it would have been either stick lac or seed lac.

Step one:

“Rub lac with four times its amount of water;

take 4,8 litres of this liquid, filtered through a cloth,

and boil it in an earthen vessel on low heat, until a fourth of it remains.”

Andrew started by crushing the lac into grains and then rubbing it in a small amount of water, before adding it to the larger amount of water of the recipe. The recipe says to sieve this – before boiling it down. This would result in only mildly dyed water.

Boiling the water and the lac together yielded a much richer colour.

Step two:

“Add 48 g each of powdered natron, borax, and lodhra (Symplocos racemosa Roxb.).

Heat it a bit. Then, once it has cooled down, fill it into a glass bottle.”

Natron and borax help dissolving the lac (see the article by Hatchett again, especially pages 191-192 and 200-202) and extracting its dye: once they were added, the colour deepened and intensified. It’s a bit difficult to say what the lodhra (Symplocos racemosa) was meant to do. It has long been used as a mordant in textile dye processes. In The Fabric of India, Rosemary Crill (2015: 33)* mentions the ash of the Lodh tree (Symplocos racemosa) as a mordant with red dyes due to its high aluminium content. Mordants or dye fixatives set dyes on fabrics and may also intensify stains. Other sources (Singh & Purohit 2013; Naqvi 1980: 170-171) also mention lodhra as a pigment for dyeing silks or wool red. Lodhra is also a medicinal plant, though its medicinal uses are perhaps less relevant here. Its applications in ayurvedic medicine are already attested in the Carakasaṃhitā and Suśrutasaṃhitā.

In our experiment, Andrew thought the addition of lodhra powder may have intensified the colour of the lac liquid further. It’s also worth mentioning that, while the text tells us to heat this mixture for a bit, Andrew boiled it for several hours. This resulted in beetroot-like water. And similar to beetroot, this liquid stained everything it came in contact with. Very messy, but certainly a powerful dye.

And now for the final step -

Step three:

“Cook the skin of a fat fish for a day and night with this water.

When it has thickened, remove it. This is known as “fish black”.”

Andrew added fish skin and boiled the whole thing for another few hours, maybe not quite a full day and night. The previous mixture already produced a fairly strong-smelling product. However, the addition of fish skin elevated the olfactory experience by several notches. We’re talking weapons-grade smelliness. Even looking at the mixture is not pleasant. What we do for science....

Voilà, fish black! Andrew likened the final product to oily blood. Perhaps not an immediately appealing product, but now, we had all we needed for the next part of the experiment, namely, making artificial rubies. We’re still working on that. Here's a sneak peek:

And here is our film on making fish black. It was a really windy few days when we filmed, so please excuse the sound quality.

* I would like to thank Aditi Khare, PhD student at the department of History, Classics and Religion at the University of Alberta for providing me with references for the uses of lodhra.

Secondary sources:

Crill, Rosemary (2015). The Fabric of India. Harry N. Abrams.

Hatchett, Charles (1804). Analytical Experiments and Observations on Lac. Philosophical Transactions of the Royal Society of London Vol. 94, 1804, pp. 191-218. https://www.jstor.org/stable/107145

Naqvi, Hamida Khatoon (1980). Colour Making and Dyeing of Cotton Textiles in Medieval Hindustan. Indian Journal of History of Science Vol. 15 (1), May 1980, pp. 58-70.

Singh, Shyam Vir and M.C. Purohit (2013). Evaluation of colour fastness properties of natural dye extracted from Symplocos racemosa (Lodh) on wool fibres using combination of natural and synthetic mordants. Indian Journal of Fibre & Textile Research Vol. 39, March 2014, pp. 97-101.