Energy and Earth Science Vol. 7, No. 1, 2024 www.scholink.org/ojs/index.php/ees ISSN 2578-1359 (Print) ISSN 2578-1367 (Online) 10 Original Paper Textbook Error Theory about Aragonite Structure Chen Guiqing 1 & Chen Junhao 1 1 Guangzhou Jinan University 510630, Guangzhou, China Received: November 25, 2023 Accepted: December 7, 2023 Online Published: March 25, 2024 doi:10.22158/ees.v7n1p10 URL: http://dx.doi.org/10.22158/ees.v7n1p10 Abstract Science constantly discovers new theories and concepts, overturning erroneous theories and concepts. Textbooks never correct, fallacies are left to future generations. There are two erroneous theories about the structure of aragonite in textbooks: (1) The authoritative Chinese textbook “Outline of Shellfish Studies” by Zhang Xi and Qi Zhongyan believes that shells can be divided into three different crystal structures, with the middle layer being a prismatic layer that occupies the majority of the shell and is composed of calcite (cubic crystal system, hexagonal crystal cells). The shellfish academic community in China quotes many Japanese literature, and these theories may have been copied from Japan. (2) The geological crystallography book records that the structural physical properties of aragonite are unstable and will eventually transform into calcite. We use X-ray derivatives found that after a long geological time, aragonite not only did not become calcite, but also the grain is growing large: monocrystalline, calcite is still decreasing, calcite is changing to aragonite. Keywords marine biology, X-ray diffraction, Shell, Prismatic pearls, Aragonite structure, Calcite structure, Geology and crystallography 1. Introduction Recently, we consulted renowned shellfish scientist Xie Yukan from the South China Sea Institute of Oceanography, Chinese Academy of Sciences to discuss this issue. It is understood that his graduate students still believe that the prismatic layer of the shell is composed of calcite through microscopic verification. Do shellfish scientists still not know that crystal structure can only be determined by X-ray diffraction, or by observing morphology under a microscope? The German physicist Roentgen discovered X-rays on November 8, 1895! In 1959, Shinjiro Kobayashi and Tetsuko Watanabe from Japan proposed that prismatic pearls have a calcite structure. Many domestic and foreign papers have not raised objections to this, which is wrong. Japanese shellfish scientists are also unfamiliar with www.scholink.org/ojs/index.php/ees Energy and Earth Science Vol. 7, No. 1, 2024 11 Published by SCHOLINK INC. crystallography. What changes will occur when shells are buried in the ground for thousands of years? The geological crystallography book records that the physical properties of aragonite structure are unstable and will eventually transform into calcite, which has become common knowledge. Wrong, it's the transformation of calcite into aragonite structure. Aragonite gemstones are composed of minerals such as aragonite, calcite, iron oxide, and opal, and belong to secondary minerals with aragonite as the main component. Only Xizang, Penghu in Taiwan Province and Sicily in Italy produce aragonite gemstones in the world. In theory, there should not be any aragonite gemstones in the world, because after billions of years, all the aragonite structures it contains have already transformed into calcite structures. However, in reality, they still exist, indicating that this theory is incorrect. 2. Materials and Methods 2.1 Modern Shells The following shells are provided by Xie Yukan, Sanya Director of the South China Sea Institute of Oceanology, CAS. Pinctada martensi, Pinctada maxima, Hyriopsis cumingii, Cristaria plicata, Pteria (Magnavicula) penguin, Pinctada margaritifera, Pinctada nigra, Pinctada chemnitzi, Anodonta woodiana, Lamprotula mansuyi, Mactra antiquate, Arca (Anadara) granosa, Meretrix meretrix, Perna viridis, Tridacna (Chamestrachea) squamosa, (Meretrix meretrix), Nautilus pompilius, Trochous nilotticus, Turbo chrysostomus, Erosaria caputserentis, Trachycadium flavum, Macoma truncate, Corbicula fluminca， Haliotis diversicolor, Nerita albicilla, Mytilus edulis, Spondylus nicobaricus, Chama dunker and Abra profundorum. The pearl and shell is ground into powder with agate mortar and passed through a 360-mesh screen. Using the D/max-1-A type X-ray diffractometer, using the Cu target Kα ray diffraction, under the conditions of 40kV and 50mA, within 30min from 2θ range 20 0 -80 0 , the instrument uses the Plot plotter, automatically prints 2θ, the absolute intensity I and the corresponding crystal face group spacing d. Refer the above results to the international universal phase analysis (JCPDS) card to determine the crystal structure of the sample. d=0.1974nm, and the bottom crossbar of the spectral line has an aragonite structure. d=0.3030nm, and the dashed line at the bottom of the spectral line shows a calcite structure. d=0.3019, the calcite III structure with ripple at the bottom of the spectral line, and the silica structure with rod, point, and rod at the bottom of the spectral line with d=0.3336. www.scholink.org/ojs/index.php/ees Energy and Earth Science Vol. 7, No. 1, 2024 12 Published by SCHOLINK INC. 2.2 Ancient Shells In the 1980s, Huang Baoyu, a researcher at the Nanjing Institute of Paleontology, provided four kinds of ancient seashells, such as splitodonta, splitodonta radiata, Euhylidia Dui and Liunia, which were collected from 102 points in Ding Village, Xiangfen, Shanxi Province, and were all hundreds to thousands of years old. Borrowed four ancient shells from Dr. Tan Yehui and Dr. Chen Zhiyun of the South China Sea Institute of Oceanography in Guangzhou: the Clams marmosa, the smooth blue clams, the river clams and the great clams. The first three species were collected from the late Quaternary loose sedimentary rock center of Yuanzhou Production Team 1 well, Shunde, Guangdong Province. In the early 1970s. The fourth kind was extracted from Longan village water conservancy project in Shunde, Guangdong Province. Years 500 to 1,000 years. Grind as above into powder and pass through 360 mesh screen. It was diffracted by Empyrean X-ray diffractometer. 3. Experimental Results 3.1 Pearl Layer Structure of Shells Only the pearl layer of the Ostrea rivularis shell has a calcite structure. The white inner layer of the Pinna atropururea shell is also a aragonite structure, and the black luminescent part around it is a calcite structure, which is also considered a pearl layer. The pearl layer of the other shells is entirely composed of aragonite structure. Explain that the above theory is correct. 3.2 Prismatic Layer Structure of Shells At present, only the prismatic layer of the Pinna atropura shell is found to be a ca1cite structure, while the loose part of the Ostrea rivularis shell is a calcite ca1cite-III structure. The prism layers of the other shells are all aragonite structures. This indicates that the above theory is incorrect. Some shells are too thin to be layered, so they have to undergo full shell X-ray diffraction. The majority of the entire shell of Spondylus nicobaricus, Haliotis diversicolor, Nerita albicilla, Mytilus edulis, Chama dunker, and Abra profundorum are also aragonite structures. 3.3 The Periostracum Layer Structure of Shells Contains a large amount of amorphous organic matter. Some shells also contain aragonite structures. Some shells also contain calcite structure ca1cite. The “Outline of Shellfish Science” states that it is incorrect for the stratum corneum of shells to be composed solely of “conchiolin”. 3.4 Prismatic Pearls Are All of Aragonite Structure, Without Calcite Structure 3.5 Schistodesmus Sp. Prismatic Layer Wilderness number ADY201, 1983/9/9. All spectral lines are aragonite structure, no impurity spectral lines. www.scholink.org/ojs/index.php/ees Energy and Earth Science Vol. 7, No. 1, 2024 13 Published by SCHOLINK INC. 3.6 Schistodesmus Lampreyanus (Baird & Adams) Prismatic Layer Wilderness number ADY201, 1986/12/16. All spectral lines are aragonite structure, no impurity spectral lines. 3.7 Unio Douglasiae Griffith et Pidgeon Wilderness number ADY201,1986/12/16. 3.7.1 Unio Douglasiae Pearl Layer The only weak spectral line of calcite appears, with a relative aragonite content of 0.15% in calcite. All other spectral lines are aragonite structured. 3.7.2 Unio Douglasiae Periostracum Layer All spectral lines are aragonite structure. 3.8 Lamprotula Hazinic (Heude) Shell Wilderness number ADY193, 1986/12/16. 3.8.1 Lamprotula Hazinic Pearl Layer All spectral lines are aragonite structure, no impurity spectral lines. 3.8.2 Lamprotula Hazinic Prismatic Layer The only weak spectral line of calcite is d104=0.3034nm. The relative content of calcite is 0.23%. All other spectral lines are of aragonite structure. 3.8.3 Lamprotula Hazinic Periostracum Layer The only weak spectral line of calcite is d104=0.3024nm. The relative aragonite content is 0.17%. All other pectral lines are aragonite. 3.8.4 Pearl Cores Made from Modern Lamprotula Hazinic Shells All spectral lines are aragonite structure. 3.9 Trapezidae, Trapezium Liratum (Reeve, 1843) Periostracum Layer The results are shown in Table 1, the same below. Two strong silica spectral lines appeared with d=0.3370nm and I/I0=70.2%; d=0.1824nm, I/I0=56.00%, which is the silica that ancient shells have adhered to in soil for many years, because modern shells have never seen these spectral lines; All other spectral lines are of aragonite structure. 3.10 Corbulidae, Potamacorbula Laevis (Hinas) Periostracum Layer All spectral lines comply with card 041-1475, All pectral lines are aragonite structure, no impurity spectral lines. 3.11 Corbiculidae, Corbicula Fluminea (Müller) 3.11.1 Corbicula Fluminea Prismatic Layer All spectral lines are aragonite structure, no impurity spectral lines. 3.11.2 Corbicula Fluminea Periostracum Layer The majority of the spectral lines below the second strongest in the table are aragonite structures. Two weak calcite spectral lines appeared: d104=0.3033nm, I/I0=8.71%, and d113=0.2282nm, I/I0=7.26%. www.scholink.org/ojs/index.php/ees Energy and Earth Science Vol. 7, No. 1, 2024 14 Published by SCHOLINK INC. The strongest spectral line of aragonite is d=2697nm, and I/I0=67.1%. The strongest spectral line of calcite is d=0.3033nm, and I/I0=8.71%. The relative aragonite content of calcite is 1.2%. The strongest spectral line d=0.3336nm is the strongest spectral line of silica SiO2, and the spectral line d=0.4249nm is the second strongest spectral line d100=0.4255nm of silica SiO2. There is also a spectrum line d=0.3205 nm and I/I0=18.38%, which is unknown. The stratum corneum of river clams contains a high amount of silica, which has been stuck in the soil for many years, because modern shells have never seen these spectral lines. If it is removed, it still has a relatively complete aragonite structure, and the aragonite spectral lines of ancient river clam shells are the same as those of modern river clam shells, without any changes. 3.11.3 Modern Corbicula Fluminea Prismatic Layer The only weak impurity mass spectrum line appeared, d=0.3632nm, I/I0=3.21%, and All other spectral lines are of aragonite structure. 3.12 Corbiculidae, Corbicula Maxima Prismatic Layer Excavated from the Longyan Village Water Conservancy Project in Shunde, Guangdong. Collection time: February 1961. 3.12.1 Corbicula Pearl Layer The X-ray diffraction pattern is very special, with the absolute intensity of the strongest spectral line d=0.2875nm reaching I=4290.7 (the maximum intensity of the spectral line in a typical shell is about 700). The spectral lines are very strong, narrow, and few, all of which are thick aragonite grains with a strong “single crystal tendency” and no impurities. Unlike geological crystallography, where the structure of aragonite is unstable, it will eventually become calcite. Instead, it develops towards a higher degree of crystallization, indicating that the structure of aragonite is stable. According to the Scherrer formula of X-ray diffraction theory of crystals, the strengthening, narrowing, and decreasing of spectral lines are caused by the growth and thickening of grains in this diffraction direction (preferential orientation growth), which we refer to as the “single crystal tendency”. The growth process of the shell pearl layer is the process of aragonite crystal growth, constantly in an unbalanced state. Due to vacancies or impurities filling the lattice, the lattice distortion changes the crystal plane group spacing d, causing the spectral lines to widen and continuously generating new internal stresses. After the death of shellfish, crystal growth stops and no new internal stress is generated. The stress inside the shell gradually releases, vacancies are gradually filled or impurities are gradually eliminated to the grain boundary to eliminate internal stress. At this time, internal stress is also concentrated at the grain boundary, so this area is prone to weathering. The grains of aragonite continue to grow, therefore; Make the spectral lines stronger, narrower, and fewer! Due to the large size of the clam shell, it is less affected by the surrounding soil, which better reflects this process. www.scholink.org/ojs/index.php/ees Energy and Earth Science Vol. 7, No. 1, 2024 15 Published by SCHOLINK INC. 3.12.2 Corbicula Prismatic Layer It X-ray diffraction pattern of the prismatic layer of the clam shell is similar to that of the pearl layer, with strong, narrow, and few spectral lines. All spectral lines are thick aragonite grains with a “single crystal tendency”, and there are no impurity spectral lines. The prism layer is between the nacre and the stratum corneum, and the internal stress release is slower, so the spectral lines are slightly more than the nacre. 3.13.3 Corbicula Periostracum Layer All spectral lines are aragonite structure, no impurity spectral lines. According to the X-ray diffraction diagram of the corneum of large corbicula shell on the right of FIG.1, the absolute intensity of the strongest spectral line d=0.1980nm I=481.16. Due to the large amount of amorphous organic matter in the corneum, the monocrystallization is affected, which greatly reduces the absolute intensity and slightly increases the spectral line. Once again proved the ancient shell monocrystalline trend! Table 1. X-Ray Diffraction Data Various Shells Pinctada martensi pearl layer Pinctada martensi prismatic layer Pinctada martensi periostracum Pinctada maxima pearl layer Pinctada maxima prismatic layer Pinctada maxima periostracum Perna viridis pearl layer d (nm) I/I0 (%) d (nm) I/I0 (%) d (nm) I/I0 (%) d (nm) I/I0 (%) d (nm) I/I0 (%) d (nm) I/I0 (%) d (nm) I/I0 (%) 0.3387 100 0.3394 79.2 0.3020 100 0.3397 100 0.3391 55.8 0.303 1 100 0.339 0 69.88 0.3264 48.8 0.3270 44.3 0.2483 12.6 0.3272 47.3 0.3266 30.3 0.248 8 12.1 0.326 8 37.01 0.3018 5.76 0.3026 13.5 0.2274 13.8 0.2702 65.7 0.2697 100 0.227 9 14.5 0.269 7 100 0.2695 77.4 0.2699 100 0.2084 13.7 0.2483 39.2 0.2481 32.8 0.208 9 11.8 0.248 1 38.47 0.2368 51.6 0.2371 47.2 0.1904 13.8 0.2373 46.4 0.2369 43.8 0.190 9 15.4 0.236 9 44.8 0.1972 46.3 0.1975 38,9 0.1867 13,7 0.1976 51.7 0.1973 27.3 0.187 1 12.9 0.197 3 34.58 www.scholink.org/ojs/index.php/ees Energy and Earth Science Vol. 7, No. 1, 2024 16 Published by SCHOLINK INC. Table 2. Continued Table 1 Perna viridis prismatic layer Perna viridis periostracum Pinna atropurpurea pearl layer Pinna atropurpurea prismatic layer Pinna atropurpurea periostracum Hyriopsis cumingii Full shell Cristaria plicata Inner middle layer d (nm) I/I0 (%) d (nm) I/I0 (%) d (nm) I/I0 (%) d (nm) I/I0 (%) d (nm) I/I0 (%) d (nm) I/I0 (%) d (nm) I/I0 (%) 0.3392 100 0.340 1 100 0.3402 58.81 0.3854 12.33 0.3028 100 0.3401 61.1 0.3400 65.4 0.3269 58.06 0.327 6 66.98 0.2876 39.16 0.3034 100 0.2486 13.78 0.3277 34. 1 0.2874 39.6 0.2699 70.44 0.270 5 55.07 0.2706 100 0.2282 17.01 0.2277 14.59 0.2704 100 0.2703 100 0.2370 52.06 0.248 6 43.17 0.2487 41.81 0.2091 14.37 0.2087 13.67 0.2374 36,3 0.2484 38.6 0.1975 50.07 0.197 8 60.89 0.2375 36.58 0.1910 19.1 0.1908 21.35 0,1977 37.2 0.2373 40.3 0.1877 36.22 0.188 0 42.76 0.1978 37.13 0.1873 16.45 0.1870 16.51 0.1743 35,2 0,1977 40,6 www.scholink.org/ojs/index.php/ees Energy and Earth Science Vol. 7, No. 1, 2024 17 Published by SCHOLINK INC. Table 3. Continued Table 2 Cristaria plicata periostracum Ostrea rivularis inner layer Ostrea rivularis Loose part Ostrea rivularis Lower shell surface Ostrea rivularis Upper shell surface Prismatic pearl powder Prismatic pearl inner surface layer d (nm) I/I0 (%) d (nm) I/I0 (%) d (nm) I/I0 (%) d (nm) I/I0 (%) d (nm) I/I0 (%) d (nm) I/I0 (%) d (nm) I/I0 (%) 0.3421 100 0.3032 100 0.3831 8.9 0.3032 100 0.303 1 100 0.340 2 95.03 0.2755 20.33 0.3295 54.3 0.2491 5.5 0.3019 100 0.2491 11.2 0.249 0 10.3 0.327 8 50.40 0.2716 100 0.2716 83.3 0.2281 10.1 0.2274 14.8 0.2281 16.8 0.228 0 15 0.270 8 100.00 0.2499 19.89 0.2495 43.1 0.2091 6.9 0.2085 11.4 0.2091 12.3 0.209 0 13 0.248 6 35.94 0.2383 19.36 0..238 3 42.8 0.1909 24.4 0.1904 17.7 0.1909 20.0 0.190 9 20.7 0.237 8 40.89 0.1822 16.97 0.1983 77.7 0.1873 14.3 0.1868 17.4 0.1872 17.6 0.187 2 17.4 0.2335 22.42 0.1751 41.15 www.scholink.org/ojs/index.php/ees Energy and Earth Science Vol. 7, No. 1, 2024 18 Published by SCHOLINK INC. Table 4. Shell X-ray Diffraction Data Schistodesmus sp. prismatic layer Schistodesmus lampreyanus prismatic layer Unio douglasiae pearl layer Unio douglasiae Periostracum layer Lamprotula sp. pearl layer Lamprotula sp. prismatic layer Lamprotula sp. Periostracum layer Modern Lamprotula sp.Pearl nuclei d nm I/I0% d nm I/I0% d nm I/I0% d nm I/I0% d nm I/I0% d nm I/I0% d nm I/I0% d nm I/I0% 0.3400 91.4 0.3398 73.2 0.3399 66.6 0.3397 100 0.3399 58.9 0.340 1 100 0.3397 100 0.3395 53.9 0.3275 48.4 0.3274 43.6 0.3275 35 0.3274 51.6 0.3274 31.3 0.327 7 51 0.3274 51 0.3273 31.9 0.2702 100 0.2702 100 0.3038 1.64 0.2700 63.2 0.2702 100 0.303 4 2.6 0.3024 1.9 0.2700 100 0.2484 52.9 0.2484 42.9 0.2702 100 0.2483 38.3 0.2484 37.3 0.270 3 61 0.2482 31.4 0.2483 32.9 0.2373 55.4 0.2373 46.9 0.2484 40.4 0.2371 37.6 0.2373 40.3 0.237 3 39.8 0.2338 35 0.2371 31.6 0.1977 52.9 0.1976 39.5 0.2373 41.2 0.1976 61 0.1976 29.4 0.197 7 64.8 0.1976 76.3 0.1976 31.9 Table 5. Continue Table 4 Trapezium liratum periostracum layer Potamacor bula laevis periostracum layer Corbicula fluminea prismatic layer Corbicula fluminea periostracum layer Modern Corbicula fluminea prismatic layer Corbicula maxima pearl layer Corbicula maxima prismatic layer Corbicula maxima periostracum layer d nm I/I0% dnm I/I0 % d nm I/I0 % d nm I/I0 % d nm I/I0 % d nm I/I0 % d nm I/I0 % d nm I/I0 % 0.3418 100.00 0.2885 23.50 0.3404 31.86 0.4249 17.42 0.3632 3.21 0.2875 100.0 0.2879 10.97 0.3399 90.81 0.3370 70.20 0.2725 76.00 0.3282 15.23 0.3336 100.0 0.3409 100.0 0.2706 58.06 0.2709 100.00 0.3279 54.75 0.2121 13.89 0.2705 100.00 0.2706 100.0 0.3033 8.71 0.3285 50.6 0.1744 2.09 0.2492 16.96 0.2703 54.46 0.1989 78.70 0.2488 49.58 0.2491 31.42 0.2697 67.10 0.2709 94 0.1438 5.77 0.2378 27.43 0.2377 56.42 0.1890 59.93 0.2375 54.28 0.2377 51.42 0.2485 30.65 0.2377 53.6 0.1415 32.81 0.2334 13.13 0.1980 100.0 0.1824 56.00 0.2332 25.17 0.2332 22.73 0.2282 7.26 0.1980 52.4 0.1361 3.21 0.1747 42.95 0.1883 50.92 www.scholink.org/ojs/index.php/ees Energy and Earth Science Vol. 7, No. 1, 2024 19 Published by SCHOLINK INC. Table 6. Relative Aragonite Content of Calcite in Ancient and Modern Shells The content of calcite relative aragonite in ancient shells is less than 2%, which is negligible Schistodesmus sp. Shell prismatic layer 0% Lamprotula hazinic Shell prismatic layer 0.23% Corbicula fluminea shell periostracum layer 0.78% Schistodesmus lampreyanus shell prismatic layer 0% Lamprotula hazinic Shell prismatic layer 0.17% Corbicula maxima shell pearl layer 0% Unio douglasiae shell pearl layer 0.15% Trapezium liratum shell periostracum layer 0% Corbicula maxima shell mprismatic layer 0% Unio douglasiae shell periostracum layer 0% Potamacor bula laevis shell periostracum layer 0% Corbicula maxima shell periostracum layer 0% Lamprotula hazinic shell pearl layer 0% Corbicula fluminea shell prismatic layer 0% Calcite relative aragonite content in modern shells Pinctada martensi shell periostracum layer 100% calcite Pinctada chemnitzi shelll periostracum layer 100% calcite Haliotis diversicolor shell 8.3% Pinctada maxima shell periostracum layer 100% calcite Ostrea rivularis Gould shell Most of the majority 100% calcite Nerita albicilla shell 14% Pteria (Magnavicula) Penguin shell periostracum layer 100% calcite Pinna atropurpurea Sowerby Shell prismatic layer 100% calcite Mytilus edulis shell 22% Pinctada margaritifera shell periostracum layer 100% calcite Pinna atropurpurea Sowerby shell periostracum layer 100%c alcite Chama dunker shell 15% Pinctada nigra Shell periostracum layer 100% calcite Spondylus nicobaricus shell 8.5% Abra profundorum shell 19% www.scholink.org/ojs/index.php/ees Energy and Earth Science Vol. 7, No. 1, 2024 20 Published by SCHOLINK INC. Position [°2Theta] (Copper (Cu)) 10 20 30 40 50 60 70 Counts 0 1000 2000 3000 4000 SCSMBC007426 NC Position [°2Theta] (Copper (Cu)) 10 20 30 40 50 60 70 Counts 0 1000 2000 3000 SCSMBC007426 ZC Position [°2Theta] (Copper (Cu)) 10 20 30 40 50 60 70 Counts 0 200 400 600 800 SCSMBC007426 WC Corbicula maxima X-ray diffraction pattern: Figure 1. Pearl Layer. Figure 2. Prismatic Layer. Figure 3. Periostracum Layer 3. Research Conclusion 3.1 The “Outline of Conchology” believes that it is correct that the nacreous layer of the shell is aragonite structure, but the peral layer of the oyster shell and the black shiny nacreous layer of the purple cracker are calcite structure. 3.2 The “Outline of Conchology” believes that it is wrong that the prismatic layer of shell is calcite structure. At present, only the prismatic layer of oyster shell and purple cracked jade is calcite structure, and the prismatic layer of other shells is aragonite structure. 3.3 The “Outline of Conchology” believes: That the Stratum corneum of a shell is composed of only conchiolin. This theory is flawed. Most of them have calcite structure, and a few have aragonite structure! www.scholink.org/ojs/index.php/ees Energy and Earth Science Vol. 7, No. 1, 2024 21 Published by SCHOLINK INC. 3.4 Shinjiro Kobayashi, a Japanese scholar, proposed in 1959 that prismatic pearls have a calcite structure in his “Pearl Research”. Why does prismatic pearls lack luster? Because its nacreous thickness is a=0.384 millimeters, the normal nacreous thickness is b=0.613 millimeters (thicker nacreous layers can reach 0.92 millimeters or more), with many fewer layers, resulting in a lack of birefringence effect, resulting in a lack of pearl luster and oil luster. It also causes the pearl nucleus to have strong reflection light, and after interference, it appears earthy yellow. This is the reason why prismatic pearls lack pearl luster. 3.5 From the X-ray spectra of the Corbiculidae, Corbicula maxima pearl layer, prism layer, and keratin layer of the clam shell buried in the ground for thousands of years, it can be seen that the structure of aragonite is developing towards a higher degree of crystallization-“single crystal”, indicating that the aragonite grains are getting larger and more stable over time. 3.6 Modern shells contain some calcite, but ancient shells have almost no calcite. After a long period of time, calcite has turned into aragonite in shells! The records in geological crystallography books and textbooks are incorrect. 3.7 Other ancient shells besides the Corbicula maxima shells also have changes in decreasing, narrowing, and strengthening spectral lines over time. However, shells that are too thin and not completely layered are easily affected by the stratum corneum. It is better to use thicker shells for detection! 3.8 The Rest of the Ancient Shells Are Small and Not Easily Stratified 3.9 X-ray diffraction from the prismatic layers of ancient shells once again confirms that the prismatic layers of shells are all aragonite structures. Funding 90 year old commemorative works III Fund project “Artificial growth of aragonite crystals and artificial development of pearls” Chen Guiqing, Chen Junhao 1985 (Approval No. 85084). Fund project “Research on the Structure and Imaging Mechanism of Artificial Pearl Cores and Artistic Image Pearls” Chen Guiqing, Chen Junhao 1989 (Approval number 890xx). www.scholink.org/ojs/index.php/ees Energy and Earth Science Vol. 7, No. 1, 2024 22 Published by SCHOLINK INC. References Chen, G. Q., & Chen, J. H. (2017). New Conclusion on the Crystal Structure of Pearls and Shells. Journal of Applied Oceanography, 36(4). Chen, G. Q., Chen, J. H., & Chen, P. (1986). A study on the natural pearls and shells of Pinctada martensii. Marine Medicine, 1986(3), 4-7. Chen, G. Q., Chen, J. H., & Zhang, X. J. (1985). X-ray diffraction study on the shell of Jinjiang oyster. Marine Medicine, 1985(3), 4-6. Chen, J. H., & Chen, G. Q. (2018). Crystal Structure and Application Exploration of Pearls and Shellfish. Jinan University Press. Chen, J. H., & Chen, G. Q. (2019). The Ancient Shells Were Sdudied by X-ray Diffraction and Electron probes. Journal of Water Resources and Ocean Science, 8(6), 86. https://doi.org/10.11648/j.wros.20190806.11 Kaiichi, M. (1965). Zhenzhu Chronicle, Beilongguan. Kobayashi, S., & Watanabe, T. (1961). Research on pearls 169-176. Technical Hall. Rock and Mineral Research Office, Department of Geology, Nanjing University. (1978). Crystallography and Mineralogy. Beijing: Geological Publishing House. Zhang, X., & Qi, Z. Y. (1961). Outline of Conchology. Science Press. Zhao, S. R. (Ed.). Crystallography and Mineralogy (p. 412). Geological Publishing House. Curriculum textbooks for higher education in the 21st century. https://doi.org/10.11648/j.wros.20190806.11