1. Introduction

The Qur’an is believed by Muslims to have divine origins and is considered a holy book that provides guidance for humanity. While it shares similarities with other scriptures, it is believed to go beyond them in its teachings. Although not a scientific text, the Qur’an discusses natural phenomena and the role of natural factors in their occurrence. This has sparked debate among contemporary thinkers, with both supporters and opponents of the idea. Therefore, studying the Qur’an from a scientific perspective is deemed significant.

The Qur’an contains scientific statements that surpass the knowledge of the time it was revealed and are now confirmed by scientific progress (Mu’addab 2007). This serves as evidence of the divine origin or scientific miracle of the Qur’an. When studying these statements, scientists should consider factors such as Explicitness or The level of certainty in the accuracy of the statement, Validity or The level of certainty in drawing the conclusion from the statement, Accuracy The level of certainty in the reliability of the scientific information, Precedence or the level of confidence that the statement did not exist during the speaker or author's era and could not have been known through scientific progress and Authenticity or the level of certainty that the statement was made at the claimed time and by the specified speak (Talebpour, Rohani Mashhadi & Moradi 2022).

Some natural phenomena mentioned in the Qur’an are easily understandable, such as:

… We created you out of dust, then out of sperm, then out of a leech-like clot, then out of a morsel of flesh, partly formed and partly unformed …(Q. 22:5).

However, some require closer examination, like the verses:

He has let free the two Seas, meeting together: Between them is a Barrier which they do not transgress: Then which of the favors of your Lord will ye deny? Out of them come Pearls and Coral (Q. 55:19-22).

In current work, the probability of a scientific miracle in verses 55:19-22 has thoroughly examined. Firstly, the precise wording of these verses carefully analyzed. Next, whether the scientific phenomenon mentioned in these verses can be attributed to them or not, was investigated. In the third step, the scientific validity of the claim was evaluated. Finally, the precedence of this concerning human understanding during that period, was assessed. The score of each item and average score have also calculated.

2. Lexical Review 

The exact meaning of the words maraja^[1], al-baḥr^[2], yaltaqīyāni^[3], barzakh^[4] and yabghīyāni^[5] need to be studied very precisely to clarify the meaning of the verses. The meanings of these words are summarized in table1.

Table 1. The meaning of the main words of the verses (Muṣṭafawī 1989; al-Jawharī 1986; Ibn Fāris 1979; Al-Fayyūmī 1993; Ibn manẓūr 1995).

According to the meanings of the words, the verses are trying to express the meaning that the two bodies of waters come freely to a point or line into contact with connections, but no visible merging is seen due to the presence of a boundary and limit. Pearls and coral are extracted from both waters.

3. Geological Investigation

According to the verse (Q .25:53), these two great waters are sweet and salt waters or great rivers and seas or oceans.

It is He Who has let free the two bodies of flowing water: one palatable and sweet, and the other salt and bitter; yet has He made a barrier between them, a partition that is not to be passed (Q. 25:53).^[6]

A river plume is formed when a large river carrying fresh water flows into the salt water of the sea or ocean. This plume is a distinct mass of low-salinity water (sweet) that is released from the mouth of the river and enters the nearby coastal waters. In tropical systems, freshwater runoff mainly occurs during short-lived floods. These floods push freshwater through estuaries and into coastal waters, where it mixes (turbulence) with saltwater due to differences in density. The thickness of the freshwater layer is influenced by various factors such as wind stress, Coriolis force and gravity (Furnas 2011). More details about river plumes are presented in other references (Wolanski & McLusky 2011).

River or stream water discharged into coastal waters forms a shallow wedge near the mouth, which is accelerated away from the coast by gravity and buoyancy. The Coriolis force causes the flowing plume of river water to turn parallel to the coast, creating a buoyancy current. The plume eventually flattens and disperses due to turbulence as it moves along the coast (Figure 1) (Burrage et al. 2003). The exchanges between two waters does not limited to nutrients and exchange of marine organisms could occur (Giachini Tosetto et al. 2022). River plumes sweat waters mix with saline seawater so slowly that a sharp salinity gradient is produced at the plume-sea interface or border (Osadchiev et al. 2022).

Figure 1. A) The top view of plume in different hemisphere. B) Chematic section through a river plume. Figures were redesigned from (Burrage et al. 2003; Giachini Tosetto et al. 2022; Osadchiev et al. 2022)

The verses indicate the presence of a barrier that prevents rivers and seas from crossing over, yet allows for mixing. It is evident that the boundary between the river Plume and the sea/ocean allows for mixing, making Plum water the subject of these verses. Therefore, verses Q. 55:19 & 5:20 are about river water (plume) introducing seawater.

4. The formation of Pearls and Coral

4.1. The View of Science

Corals, belonging to the class of Anthozoa within the phylum Cnidaria, are sessile invertebrates that exist in a vast array of species and abundance. They can be found living in colonies or solitaries. Although corals are present in all oceans worldwide, their distribution is limited to the latitudes between the Tropic of Cancer and the Tropic of Capricorn (Spalding, Ravilious & Green 2001). The factors that determine their distribution include biotic elements such as coral's intra and interspecific competitions, corallivores, reproductive and recovery capacity, as well as their ability to withstand environmental stress. Abiotic factors such as light, water temperature, pH, salinity, turbidity, and depth also play a significant role (Howes, Birchenough & Lincoln  2018). Altering these parameters can have a severe impact on coral health and survival (Siro et al. 2022). The body structure of corals is uncomplicated and comprises a sac-like body with retractable tentacles that possess nematocysts, which are stinging cells. The coral has two tissue layers, namely the gastrodermis and epidermis, which are separated by a gelatinous matrix known as the mesoglea. These layers originate from the endoderm and ectoderm during the coral's life cycle (Barott et al. 2015). Corals can be categorized into two types based on their physical texture: hard coral and soft coral. Hard corals, also known as stony corals or scleractinian corals, possess an outer skeleton composed of calcium carbonate (CaCO3) arranged in a crystalline form called aragonite. The hermatypic stony corals that form reefs grow by shedding CaCO3 skeletons, which is an essential component of reef formation and structure. These hermatypic corals are crucial calcifying organisms that contribute to the biodiversity of coral reefs. Conversely, soft or ahermatypic corals have small spikes of calcium carbonate embedded within their bodies (Spalding, Ravilious & Green 2001). The chemical composition of Pearls and Coral are presented in table2.

Table 2. Chemical composition of Pearls and Coral (Pearls and other organic gems n.d.; Furnas 2011)

Biomineralization is a natural process that results in the formation of various solid inorganic structures by living organisms. This phenomenon is widespread and can be observed in prokaryotes, protozoa, algae, invertebrates, plants, and even pathological biominerals. The process involves converting ions into solid minerals through reaction and precipitation. Organisms use their synthetic organic macromolecules to manipulate the process of inorganic crystal nucleation, growth, and molecular arrangements to produce minerals with unique properties such as optical, magnetic, and mechanical properties (Arias & Fernández 2008; Zhang, Xie & Yan 2019) .

Corals undergo biomineralization through a process called calcification; CO2 molecules are absorbed by the ocean and combined with calcium ions to form calcium carbonate. This process is primarily carried out by calcifying organisms, including corals, molluscs, calcareous algae, foraminifera, sponges, and echinoderms, with corals being the primary producers of calcium carbonate precipitates. For corals to survive, they require specific physiological and environmental conditions. They thrive in temperatures between 18 and 30 °C and a salinity range of 32 to 40% (Souter & Lindén 2000).

The process of biomineralization in Pinctada pearl oysters, specifically fucata, involves the uptake of precursor ions such as Ca2+ and HCO3- from the surrounding environment. This is facilitated by the body epithelium or gill, which may also originate from food sources. The ions are then transported through the hemolymph and directed towards the outer mantle epithelium. Under precise regulation, significant amounts of calcium ions are continuously deposited onto the framework (Zhang, Xie & Yan 2019).

4.1.1. The Role of Sea and River

Coral and Pearls constructed from calcium ions, so the formation of coral and pearls requires and consumes calcium ions. Therefore, the concentration of calcium in seawater will decrease over time if there is no supply of calcium. Coral and pearls cannot form in low concentrations of calcium. Without a continuous supply of calcium, their formation will decrease and stop. What is the sources of calcium of seawater?

Calcium is supplied to the oceans mainly by rivers, but also by hydrothermal circulation, with Calcium derived from the alteration of the continental and oceanic crust (Holland 1984; Milliman 1993; Schmitt Chabaux & Stille 2003; Griffith et al. 2008). Rock weathering is estimated that is two thirds of riverine Calcium ions at a global scale. Over geological time-scales, Ca is released from silicate minerals during weathering of both the continental and oceanic crust, and transferred to the carbonate reservoir. According to a research, approximately one-third of the total Calcium ion supplied by rivers to the oceans (Tipper et al. 2010). The balance of Calcium ions depends on riverine completely.

Supplying of nutrients especially calcium is necessary for formation and growth of coral and pearls. Rivers and specially runoff waters are one main suppliers of these nutrients, so they have a main and necessary role in formation of coral and pearls (Gagan, Sandstrom & Chivas 1987; Devlin & Brodie 2005; Furnas 2011).

The formation of coral and pearls relies on the presence of Calcium and other nutrients. These essential elements are obtained by Coral and Nacre from seawater, with the majority of Calcium and nutrients being supplied by rivers.

4.2. The View of the Qur’an

According to the Qur’an, coral and pearls are formed through a process involving both river and sea waters. This suggests that there are certain elements present in these waters that are necessary for the formation of these precious gems. It is possible that these elements differ between the two types of water, or they may be the same. Regardless, they must be extracted from both sources and transferred to the pearls and coral for their formation.

4.2.1. Precedence of the Verses

The focus of this discussion is on whether people during the time of the Qur’an revelation had knowledge about the formation of coral and pearls. To answer this question, it is necessary to examine historical data on their origin and formation.

Pliny the Elder (23–79 AD) in his book Naturalis Historia described coral's shapes, sizes, values, behavior, types and usages but no about chemical composition or condition of formation (Pliny the Elder n.d.). The information about pearls is even more limited, and nothing about the composition of pearls is mentioned. Manusmriti, an old Indian book, mentioned pearls and coral without any details too. Bīrūnī (973-1048 AD) in his comprehensive book al-Jamāhir fī al-Jawāhir (Kitāb al-Jamāhir fī Maʿrifah al-Jawāhir) has discussed pearls very comprehensive and in details and supposed coral as pearls. He discussed names, characteristics, humidity, prices, correctness, essence, shells and occurrences, diving et al. But nothing shows that he or other scientists or that era were aware of chemical composition of pearls (Bīrūnī 2001) .

Centuries later, Donati examined the body of corals in his discoveries (Donati 1752). He attempted to convert the coral body to ash using fire but was unable to determine the origin of the coralline substance or the presence of lime or calcium. It was not until Hatchett's discovery in 1800 that it was revealed that nacre, pearls, and coral are made from lime (Hatchett 1800). Calcium was discovered by Humphry Davy in a series of experiments in 1808 (Davy 1808). He tried to reduce moist lime by electrolysis in various condition and ultimately discovered the Calcium element. Davy conducted the experiments with equipment and knowledge that were not available until centuries. Silliman Jr. quantitatively analyzed many corals and measured their calcium contents in 1846 (Silliman Jr 1846). Following these discoveries, scientists recognize the impact of seawater's calcium ion concentration on Coral and Pearls formation, an example is Darwin assertion:

"It will, perhaps, be suggested, that the quantity of carbonate of lime in different parts of the sea, may regulate the presence of [Coral] reefs" (Darwin 1842).

Figure 2. The timeline of history of knowledge about formation of pearls and coral. The first development is at 1800.

The timeline of this history is presented in Figure 2. Although there is no evidence to suggest that scientists during the time of the Qur’an revelation were aware of the existence of a lime-like compound in coral and pearls, it is possible that an unknown individual who did not publish any texts may have known about it. However, given the limited scientific knowledge and technology of that era, it is not possible that they were aware of calcium's existence in corals, pearls, and seawater. Without this knowledge, they would not have been able to identify the process by which calcium moves from rivers to seawater via plumes or how it is extracted from seawater by Coral and Nacres. Therefore, it can be concluded that the role of both rivers and seas in the formation of pearls and coral was not known during the time of the Qur’an revelation.

5. Comparison of Two Views

The verses state that coral and pearls are formed by the waters of rivers and seas. The scientific facts presented in the section 4.1 confirm the accuracy of this statement. Notably, the verb yakhruju^[7] (extract) is used in the verse. This can refer to how corals and Pinctadas extract elements from seawater, which is then obtained by the sea from river runoff. Extraction involves separating a part of something (in this case, ions) from the whole (water). The verses lacked clarity on the extracted element(s), which is mainly Calcium ion. The wording of these verses is scientifically sound and accurate, with no contradictions between them and scientific knowledge. The scores of Explicitness, Validity and Accuracy are 0.9/1, 1/1 and 1/1 respectively. These scores and score of precedence and Authenticity are presented in table 3. The overall is 0.93/1 by formula was provided by Talebpour, Rohani Mashhadi and Moradi (2022).

Table 3. The scores of main parameters of possibility of the miracle in verses.

6. Conclusion

The first phenomenon described in the verses pertains to the meeting point of river plume/runoff water and sea/ocean. The descriptions in the Qur’an align with physics, too. Although the Qur’an's descriptions may have been far ahead of their time, this aspect was not studied here. The second phenomenon pertains to the formation of pearls and coral through extraction from both waters. The scientific facts and Qur’anic descriptions are completely similar. It should be noted that the Qur’an did not provide a detailed account of the entire process.

A survey of available historical data reveals that it was not possible, with the knowledge and equipment available at the time of the revelation of the Qur’an, to describe the formation of pearls and coral as accurately as stated in the Qur’an.

Achieving 100% certainty is difficult due to factors such as biases, limited information, and complexity. However, strong evidence can lead to confidence in propositions, as seen in scientific theories and legal cases. While 100% certainty may not always be possible, confidence can still be achieved through strong evidence.

The aforementioned evidence shows that verses Q. 55:19-22 possess all factors of a miracle with score of 0.93/1. However, further research is necessary before claiming it as a miracle, and it is important to consider other scientists' opinions on this matter.