Glass (काचः) - Revision history

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Foreign travel accounts like Pliny’s Naturalis Historia (73—77 AD; translated by Bostock and Riley as The Natura1 History of Pliny in 1890), Periplus Maris Erythraei (considered to be earlier than Naturalis Historia; translated by Schoff as Periplus of the Erythrean Sea in 1912) and Geography of Strabo (17—23 AD); translated by Jones and cited in Majumdar 1960: 279, 394) considered Indian glass to be of high quality as it was made of pounded quartz rather than silica. It has long been suggested that this may have been the reason behind the high silica content in ancient Indian glass.<ref name=":0">Kanungo, A. (2008). Glass in India. In ''Development of Glass in India'' (pp. 1023–1033). <nowiki>https://doi.org/10.1007/978-1-4020-4425-0_9743</nowiki></ref>

=== Technical terms ===
Archeometric studies reveal that glass gradually evolved through experimentation by early man with various siliceous materials with the help of pyro-technology.<ref name=":2">Bharadwaj. H. C. (1997) ''History of Technology in India, Vol. 1, From Antiquity to c. 1200 A.D.'' New Delhi: Indian National Science Academy. (Chapter Glass: 208 - 225)</ref> In dealing with ancient glass objects, it is necessary to differentiate glass from glaze and faience, which have some common ingredients and present some identical superficial effects, but are not true glass.<ref name=":3">Sen, N., & Chaudhuri, M. C. (1985). ''Ancient Glass and India''. Indian National Science Academy.</ref>

* '''Glass''': Glass is a material created by fusing materials like sand, soda, and lime at high temperatures. The chemical name for glass is SILICON DIOXIDE (Si02). Common names for glass are silica, sand, quartz and flint. Silicon dioxide is one of the most common minerals composing the earth and can be easily found in most parts of the world. Glass and glaze are chemically identical but are worked and used differently.
* '''Glaze''': A glaze is a vitreous substance which is applied in thin layers to another substance acting as the core material. Thus glaze is a glassy layer applied to a core or base of some other material.<ref name=":0" />
* '''Faience''': Faience (glazed siliceous ware) has powdered quartz core with an over glaze, which is soda-lime-silica glass, and is isotropic in nature.<ref name=":2" /> Faience consists of a lightly sintered core of crushed quartz grains coated with a translucent blue-to-green glaze, both fluxing due to soda.<ref name=":0" />

=== Glass in Ancient Indian Literature ===
Mention of glass (kaca काच) and its by-products, most prominently that of beads, occurs in [[Brahmana (ब्राह्मणम्)|Brahmanas]] such as Satapatha Brahmana and Buddhist literature Mahavagga, Cullavagga. The use of the word kaca (काच) for glass was common in daily life during the times of Buddha and thereafter found frequently in Sanskrit and Pali literature. In Yajurveda, kaca (काच) is mentioned as one the articles of which ladies ornaments were made by stringing with gold thread. In Satapatha Brahmana kaca may mean glass beads which were used for decorating horses in the ashvamedha yajna.<ref name=":3" /><blockquote>एवमेतत्पशो स्कन्दति यस्य निक्तस्य लोमानि शीयन्ते '''यत्काचाना'''वयन्ति लोमान्येवास्य सम्भरन्ति हिरण्मया भवन्ति तस्योक्तं ब्राह्मणमेकशतमेकशतं '''काचानावयन्ति''' शतायुर्वै पुरुष आत्मैकशत आयुष्येवात्मन्प्रतितिष्ठति.. (Sata. Brah. 13.2.6.8)<ref>Satapatha Brahmana ([https://sa.wikisource.org/wiki/%E0%A4%B6%E0%A4%A4%E0%A4%AA%E0%A4%A5%E0%A4%AC%E0%A5%8D%E0%A4%B0%E0%A4%BE%E0%A4%B9%E0%A5%8D%E0%A4%AE%E0%A4%A3%E0%A4%AE%E0%A5%8D/%E0%A4%95%E0%A4%BE%E0%A4%A3%E0%A5%8D%E0%A4%A1%E0%A4%AE%E0%A5%8D_%E0%A5%A7%E0%A5%A9/%E0%A4%85%E0%A4%A7%E0%A5%8D%E0%A4%AF%E0%A4%BE%E0%A4%AF%E0%A4%83_%E0%A5%A8/%E0%A4%AC%E0%A5%8D%E0%A4%B0%E0%A4%BE%E0%A4%B9%E0%A5%8D%E0%A4%AE%E0%A4%A3_%E0%A5%AC Kanda 13 Adhyaya 2 Brahmana 6])</ref>

evametatpaśo skandati yasya niktasya lomāni śīyante yat'''kācā'''nāvayanti lomānyevāsya sambharanti hiraṇmayā bhavanti tasyoktaṃ brāhmaṇamekaśatamekaśataṃ '''kācā'''nāvayanti śatāyurvai puruṣa ātmaikaśata āyuṣyevātmanpratitiṣṭhati..</blockquote>Taittriya brahmana also states that glass beads of various colors were used to decorate the manes and tails of horses.<ref name=":3" /><blockquote>यद् वालेषु काचान् आवयन्ति । .... हिरण्ययाः काचा भवन्ति । (Tait. Brah. 3.9.4.4-5)<ref>Taittriya Brahmana (See [https://sa.wikisource.org/wiki/%E0%A4%A4%E0%A5%88%E0%A4%A4%E0%A5%8D%E0%A4%A4%E0%A4%BF%E0%A4%B0%E0%A5%80%E0%A4%AF%E0%A4%AC%E0%A5%8D%E0%A4%B0%E0%A4%BE%E0%A4%B9%E0%A5%8D%E0%A4%AE%E0%A4%A3%E0%A4%AE%E0%A5%8D_(%E0%A4%B5%E0%A4%BF%E0%A4%B8%E0%A5%8D%E0%A4%B5%E0%A4%B0%E0%A4%AA%E0%A4%BE%E0%A4%A0%E0%A4%83) Kanda 3 Prapathaka 9 Anuvaka 4])</ref>

yad vāleṣu kācān āvayanti | .... hiraṇyayāḥ kācā bhavanti |</blockquote>According to a few scholars the manufacture of glass and colored glass is documented in ancient literature such as Ramayana, Mahabharata and ancient poetic works such as Bana's Kadambari. However, no glass objects have been recovered from Indus valley areas even though ancient Indian literature references are available. Kautilya in his Arthashastra while laying down rules for the Superintendent of the treasury talks about the identification of various kinds of gems and precious stones and mentions a few times about glass; in the context of testing gems to place them in jewelry, in trade and tax payments, robbery and fines.<ref>Krishnamurthy. Radha, (1997) ''History of Technology in India, Vol. 1, From Antiquity to c. 1200 A.D.'' New Delhi: Indian National Science Academy. (Chapter Dyes, Mordants and Pigments: Page 300 - 312)</ref>
*शेषाः काच-मणयः ।। ०२.११.३६ ।। (Arth. Shas. 2.11.36)<ref>Arthashastra ([https://sa.wikisource.org/wiki/%E0%A4%85%E0%A4%B0%E0%A5%8D%E0%A4%A5%E0%A4%B6%E0%A4%BE%E0%A4%B8%E0%A5%8D%E0%A4%A4%E0%A5%8D%E0%A4%B0%E0%A4%AE%E0%A5%8D/%E0%A4%85%E0%A4%A7%E0%A4%BF%E0%A4%95%E0%A4%B0%E0%A4%A3%E0%A4%AE%E0%A5%8D_%E0%A5%A8/%E0%A4%85%E0%A4%A7%E0%A Adhikarana 2 Adhyaya 11])</ref> rest are the glass gems.
*क्षेपणः काच-अर्पण-आदीनि ।। ०२.१३.३८ ।। (Arth. Shas. 2.13.38)<ref>Arthashastra ([https://sa.wikisource.org/wiki/%E0%A4%85%E0%A4%B0%E0%A5%8D%E0%A4%A5%E0%A4%B6%E0%A4%BE%E0%A4%B8%E0%A5%8D%E0%A4%A4%E0%A5%8D%E0%A4%B0%E0%A4%AE%E0%A5%8D/%E0%A4%85%E0%A4%A7%E0%A4%BF%E0%A4%95%E0%A4%B0%E0%A4%A3%E0%A4%AE%E0%A5%8D_%E0%A5%A8/%E0%A4%85%E0%A4%A7%E0%A Adhikarana 2 Adhyaya 13])</ref> Kshepana, guna, and kshudra are three kinds of ornamental work. Setting jewels (kácha, glass bead) in gold is termed kshepana.<ref>Shamasastry. R, ''Kautilya's Arthashastra with English Translation'' (Page 120)</ref>
*Evidence of trade of glass items<ref>Shamasastry. R, ''Kautilya's Arthashastra with English Translation'' (Page 343)</ref>
Glass (kacha) was differentiated from crystal (sphatika) as early as in the days of Susruta (Chap. 46). Archaeological evidences support the use of glass beads, bangles, jars, tiles etc. made from 6th or 5th century' B.C. onwards. Most of the glass objects were colored. Glass manufacture practiced as an indigenous industry in ancient India is seen in excavations particularly in the south (Arikamedu, Uraiyur). Along with this, the technique of coloring glass also developed. The glass specimens show that the glass makers of ancient India were highly competent in giving different colors and shades to glass objects. In the drama Vasavadatta (6th ceutury A.D.) mention has been made of glass colored like the neck of peacock.<ref name=":1">Ray, P. (1956) ''History of Chemistry in Ancient and Medieval India, incorporating the History of Hindu Chemistry by Acharya Prafulla Chandra Ray.'' Calcutta: Indian Chemical Society</ref>

Chemical analysis revealed, just like in the case of pottery, that coloring agents were obtained from the metallic ores. Different chemicals added to them finally led to attribute different shades of colors and glazes to the glass objects. Colored glass was prepared by mixing silicates of soda, lime and appropriate metallic oxides.<ref>Jaggi, O.P. (1977) ''Science and Technology in Ancient India, New Delhi. Vol I'', p.203</ref> Copper oxide, iron oxide, manganese oxides were generally used to give colors to the glass articles as for pottery. A special type of glass beads of 350 A.D. to 750 A.D. found at Ahicchatra is of gold foil glass. Layers of gold foils were poured in between two glass layers. All these prove that craftsmen in ancient India were highly skillful in the sophisticated technique of using metallic ores and chemicals as pigments in coloring very high temperature melting media like glass.

=== Archeological Evidence of Glass ===
Many scholars agree that people of Indus Valley civilization may not know glass making<ref name=":2" /><ref name=":0" /> but some scholars have tried to trace the origin of Indian glass to the Harappan civilization on the basis of finding glazed pottery and quartz beads. Harappans made glazed pottery, which is ceramic with a thin layer of glass on the surface (Tite et al. 1983). Though no true glass has been found in India from the Protohistoric periods at Mohenjodaro and Harappa, the second millennium BCE saw its people able to mould and fuse excellent articles of faience and glazing their quartz beads with frit, a material similar to glass.<ref name=":0" /> Archeological excavations brought to light many glass objects - beads, bangles, seals and ornamental pieces - from sites such as Hastinapur, Ropar, Alamgirpur, Ahicchatra, Sravasti, Kausambi, Rajghat, Kopia, Ujjain, Maski, Kodapur, Amavarati, Patliputra, Arikamedu, Bellary, Kolhapur etc, among many other places. Some of the earliest objects mainly beads and bangles were brown, black and dark-green in color.<ref name=":2" /> Black and brownish colored glass beads found at Hastinapur are mainly of soda-lime-silicate composition with traces of phosphates and potassium, as well as with varying amounts of iron compounds which are responsible for their color. A number of glass beads of different shapes and colors like blue, red, green, amber, orange and black, dark green, ear-reels with a floral design, 'eye-beads', bangles and seals have been found in the Bhir mound at Takshashila (sixth-fourth century BC).<ref name=":4">Story of Glass in India & the World by Pankaj Goyal</ref>

About 30 archaeological excavated sites in different regions of India have produced several glass objects in different colors such as green, blue, red, white, orange and some other shades. In certain places, a few tiles and fragmented parts of vessels also have been found.<ref name=":4" /> Based on evidence, the knowledge of chemistry as known by ancient Indians included<ref name=":2" />

* Soda is predominant alkali though potash is also present.
* Iron is the main coloring agent; chromium as colorant is also reported from Atranjikhera.
* Limited chemical analysis show they are low in silica
* Annealing is supposed to be have been done.

== References ==
[[Category:Chemistry]]

@@ Line 1: / Line 1: @@
 {{ToBeEdited}}
-Foreign travel accounts like Pliny’s Naturalis Historia (73—77 AD; translated by Bostock and Riley as The Natura1 History of Pliny in 1890), Periplus Maris Erythraei (considered to be earlier than Naturalis Historia; translated by Schoff as Periplus of the Erythrean Sea in 1912) and Geography of Strabo (17—23 AD); translated by Jones and cited in Majumdar 1960: 279, 394) considered Indian glass to be of high quality as it was made of pounded quartz rather than silica. It has long been suggested that this may have been the reason behind the high silica content in ancient Indian glass.<ref name=":0">Kanungo, A. (2008). Glass in India. In ''Development of Glass in India'' (pp. 1023–1033). <nowiki>https://doi.org/10.1007/978-1-4020-4425-0_9743</nowiki></ref>
+Glass (Samskrit: काचः) is a molten mixture of substances such as lime, sand, alkali and metal oxides. It comes in many forms: transparent, opaque, colored and colorless. Glass is a 'supercooled liquid' whose main component is silica. Mention of glass or kaca is profuse in the ancient Indian texts. Ample evidence suggests that glassmaking was widespread in ancient India and the craft achieved a high degree of success.<ref name=":5">Banerjee, S. (2024) Indian knowledge system: A Study of Ancient Indian Chemistry of Glass. ''International Journal of Advance and Innovative Research'', ''11,1(III) 51-54''</ref>
 === Technical terms ===
@@ Line 7: / Line 10: @@
 * '''Glass''': Glass is a material created by fusing materials like sand, soda, and lime at high temperatures. The chemical name for glass is SILICON DIOXIDE (Si02). Common names for glass are silica, sand, quartz and flint. Silicon dioxide is one of the most common minerals composing the earth and can be easily found in most parts of the world. Glass and glaze are chemically identical but are worked and used differently.
-* '''Glaze''': A glaze is a vitreous substance which is applied in thin layers to another substance acting as the core material. Thus glaze is a glassy layer applied to a core or base of some other material.<ref name=":0" />
+* '''Glaze''': A glaze is a vitreous substance which is applied in thin layers to another substance acting as the core material. Thus glaze is a glassy layer applied to a core or base of some other material.<ref name=":0">Kanungo, A. (2008). Glass in India. In ''Development of Glass in India'' (pp. 1023–1033). <nowiki>https://doi.org/10.1007/978-1-4020-4425-0_9743</nowiki></ref>
 * '''Faience''': Faience (glazed siliceous ware) has powdered quartz core with an over glaze, which is soda-lime-silica glass, and is isotropic in nature.<ref name=":2" /> Faience consists of a lightly sintered core of crushed quartz grains coated with a translucent blue-to-green glaze, both fluxing due to soda.<ref name=":0" />
-=== Glass in Ancient Indian Literature ===
+== Glass in Ancient Indian Literature ==
 Mention of glass (kaca काच) and its by-products, most prominently that of beads, occurs in  [[Brahmana (ब्राह्मणम्)|Brahmanas]] such as Satapatha Brahmana and Buddhist literature Mahavagga, Cullavagga. The use of the word kaca (काच) for glass was common in daily life during the times of Buddha and thereafter found frequently in Sanskrit and Pali literature. In Yajurveda, kaca (काच) is mentioned as one the articles of which ladies ornaments were made by stringing with gold thread. In Satapatha Brahmana kaca may mean glass beads which were used for decorating horses in the ashvamedha yajna.<ref name=":3" /><blockquote>एवमेतत्पशो स्कन्दति यस्य निक्तस्य लोमानि शीयन्ते '''यत्काचाना'''वयन्ति लोमान्येवास्य सम्भरन्ति हिरण्मया भवन्ति तस्योक्तं ब्राह्मणमेकशतमेकशतं '''काचानावयन्ति''' शतायुर्वै पुरुष आत्मैकशत आयुष्येवात्मन्प्रतितिष्ठति.. (Sata. Brah. 13.2.6.8)<ref>Satapatha Brahmana ([https://sa.wikisource.org/wiki/%E0%A4%B6%E0%A4%A4%E0%A4%AA%E0%A4%A5%E0%A4%AC%E0%A5%8D%E0%A4%B0%E0%A4%BE%E0%A4%B9%E0%A5%8D%E0%A4%AE%E0%A4%A3%E0%A4%AE%E0%A5%8D/%E0%A4%95%E0%A4%BE%E0%A4%A3%E0%A5%8D%E0%A4%A1%E0%A4%AE%E0%A5%8D_%E0%A5%A7%E0%A5%A9/%E0%A4%85%E0%A4%A7%E0%A5%8D%E0%A4%AF%E0%A4%BE%E0%A4%AF%E0%A4%83_%E0%A5%A8/%E0%A4%AC%E0%A5%8D%E0%A4%B0%E0%A4%BE%E0%A4%B9%E0%A5%8D%E0%A4%AE%E0%A4%A3_%E0%A5%AC Kanda 13 Adhyaya 2 Brahmana 6])</ref>
@@ Line 23: / Line 27: @@
 Chemical analysis revealed, just like in the case of pottery, that coloring agents were obtained from the metallic ores. Different chemicals added to them finally led to attribute different shades of colors and glazes to the glass objects. Colored glass was prepared by mixing silicates of soda, lime and appropriate metallic oxides.<ref>Jaggi, O.P. (1977) ''Science and Technology in Ancient India, New Delhi. Vol I'', p.203</ref> Copper oxide, iron oxide, manganese oxides were generally used to give colors to the glass articles as for pottery. A special type of glass beads of 350 A.D. to 750 A.D. found at Ahicchatra is of gold foil glass. Layers of gold foils were poured in between two glass layers. All these prove that craftsmen in ancient India were highly skillful in the sophisticated technique of using metallic ores and chemicals as pigments in coloring very high temperature melting media like glass.
-=== Archeological Evidence of Glass ===
+Foreign travel accounts like Pliny’s Naturalis Historia (73—77 AD; translated by Bostock and Riley as The Natura1 History of Pliny in 1890), Periplus Maris Erythraei (considered to be earlier than Naturalis Historia; translated by Schoff as Periplus of the Erythrean Sea in 1912) and Geography of Strabo (17—23 AD); translated by Jones and cited in Majumdar 1960: 279, 394) considered Indian glass to be of high quality as it was made of pounded quartz rather than silica. It has long been suggested that this may have been the reason behind the high silica content in ancient Indian glass.<ref name=":0" />
-Many scholars agree that people of Indus Valley civilization may not know glass making<ref name=":2" /><ref name=":0" />  but some scholars have tried to trace the origin of Indian glass to the Harappan civilization on the basis of finding glazed pottery and quartz beads. Harappans made glazed pottery, which is ceramic with a thin layer of glass on the surface (Tite et al. 1983). Though no true glass has been found in India from the Protohistoric periods at Mohenjodaro and Harappa, the second millennium BCE saw its people able to mould and fuse excellent articles of faience and glazing their quartz beads with frit, a material similar to glass.<ref name=":0" /> Archeological excavations brought to light many glass objects - beads, bangles, seals and ornamental pieces - from sites such as Hastinapur, Ropar, Alamgirpur, Ahicchatra, Sravasti, Kausambi, Rajghat, Kopia, Ujjain, Maski, Kodapur, Amavarati, Patliputra, Arikamedu, Bellary, Kolhapur etc, among many other places. Some of the earliest objects mainly beads and bangles  were brown, black and dark-green in color.<ref name=":2" /> Black and brownish colored glass beads found at Hastinapur are mainly of soda-lime-silicate composition with traces of phosphates and potassium, as well as with varying amounts of iron compounds which are responsible for their color. A number of glass beads of different shapes and colors like blue, red, green, amber, orange and black, dark green, ear-reels with a floral design, 'eye-beads', bangles and seals have been found in the Bhir mound at Takshashila (sixth-fourth century BC).<ref name=":4">Story of Glass in India & the World by Pankaj Goyal</ref>
-About 30 archaeological excavated sites in different regions of India have produced several glass objects in different colors such as green, blue, red, white, orange and some other shades. In certain places, a few tiles and fragmented parts of vessels also have been found.<ref name=":4" /> Based on evidence, the knowledge of chemistry as known by ancient Indians included<ref name=":2" />
+Literature mentions the use of '''reh''' or sodic soils as the only ingredient necessary to melt glass as used by ancient Indians. Depending on the region, reh is likewise known as usar, kalar, and oos - designating either the efflorescence itself or the sodic-rich soil. Reh is a soil efflorescence containing huge quantities of sodium salts (carbonate, bicarbonate and sulphate) and ranging proportions of calcium and magnesium salts. The furnace used to soften reh glass became advanced indigenously and the related pyrotechniques have been a critical part of historic Indian knowledge.<ref name=":5" />
 * Soda is predominant alkali though potash is also present.
@@ Line 32: / Line 45: @@
 * Limited chemical analysis show they are low in silica
 * Annealing is supposed to be have been done.
 == References ==
 [[Category:Chemistry]]