On the Cause of the Blue Color of Sapphire, Lazulite, and Lapis-Lazuli; the Green of Emerald and the Purple of Amethyst

1882 ◽  
Vol 14 (351supp) ◽  
pp. 5604-5605
Author(s):  
W. A. Ross
Keyword(s):  
2020 ◽  
Vol 6 (18) ◽  
pp. eaay8782
Author(s):  
Alessa A. Gambardella ◽  
Marine Cotte ◽  
Wout de Nolf ◽  
Kokkie Schnetz ◽  
Rob Erdmann ◽  
...  

Ultramarine blue pigment, one of the most valued natural artist’s pigments, historically was prepared from lapis lazuli rock following various treatments; however, little is understood about why or how to distinguish such a posteriori on paintings. X-ray absorption near-edge structure spectroscopy at the sulfur K-edge in microbeam and full-field modes (analyzed with nonnegative matrix factorization) is used to monitor the changes in the sulfur species within lazurite following one such historically relevant treatment: heating of lapis lazuli before extracting lazurite. Sulfur signatures in lazurite show dependence on the heat treatment of lapis lazuli from which it is derived. Peaks attributed to contributions from the trisulfur radical—responsible for the blue color of lazurite—increase in relative intensity with heat treatment paralleled by an intensified blue hue. Matching spectra were identified on lazurite particles from five historical paint samples, providing a marker for artists’ pigments that had been extracted from heat-treated lapis lazuli.


Author(s):  
Gulmira Kattaeva Chorievna ◽  

Lapis lazuli is one of the most attractive semi-precious stones. Due to its peculiar blue color and its rareness, it has been used since the Neolithic Period for the manufacturing of precious objects and jewels (beads, gems, seals, small decorative artworks, etc.). Scientific analysis of jewelry which was made of the lapis lazuli can help to explore deeper cultural, economic, and political relations between the ancient oases of Central Asia and the Ancient Eastern civilizations. In this article, it is cited scientific pieces of evidence about the earliest and still existing deposits of lapis lazuli sources and the ancient lapis lazuli jewelry. On top of that, it is given scientific information about the types of the lapis lazuli beads which was found from the monuments of Sapalli culture in the part of the Ancient Eastern Civilization such as Sapallitepa, Djarkutan, Mulali, Bustan VI, and also Central Asia.


1963 ◽  
Vol 9 (3) ◽  
pp. 84-101 ◽  
Author(s):  
J. Ostwald
Keyword(s):  

2015 ◽  
Vol 8 (2) ◽  
pp. 2106-2121
Author(s):  
Hamed Ibrahem Abdelkader ◽  
Mona Abdelkader ◽  
Mohammed Kabeel ◽  
Malak Alya

Visual evoked potentials (VEPS) are obtained from optic tract by recording the evoked potentials generated by retinal stimulation. The flash VEP (FVEP) is used less frequently than pattern reversal VEP (PRVEP) because; it shows great variation in both latency and amplitude. The present study was undertaken to evaluate the effect of change of wavelength of flash and change of check size on the parameters of visual evoked potential (amplitude and latency) in normal individuals and glaucoma patients. The group of healthy subjects in the age of 20-45 years while the group of glaucoma subjects where  in the age of 25-50 years.  The two groups were exposed to flash VEP with white light and blue color and they also were exposed to checks subtending a visual angles of 15, 30,60 and 120 minutes of arc. The measured data were statistically analyzed and summarized by histograms. The interindividual and intraindividual in latencies and amplitudes for FVEP were assessed using  the coefficient of variation (COV). In conclusion, monochromatic flash VEP was preferred than white as there were minimal inter and intra individual variation of latencies and amplitudes. The most preferred check size in PRVEP was 120' for  the two groups.  


Author(s):  
Carolyn Swan

Around the year 970 CE, a merchant ship carrying an assortment of goods from East Africa, Persia, India, Sri Lanka, Southeast Asia, and China foundered and sank to the bottom of the Java Sea. Thousands of beads made from many different materials—ceramic, jet, coral, banded stone, lapis lazuli, rock crystal, sapphire, ruby, garnet, pearl, gold, and glass—attest to the long-distance movement and trade of these small and often precious objects throughout the Indian Ocean world. The beads made of glass are of particular interest, as closely-dated examples are very rare and there is some debate as to where glass beads were being made and traded during this period of time. This paper examines 18 glass beads from the Cirebon shipwreck that are now in the collection of Qatar Museums, using a comparative typological and chemical perspective within the context of the 10th-century glass production. Although it remains uncertain where some of the beads were made, the composition of the glass beads points to two major production origins for the glass itself: West Asia and South Asia.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 485d-485
Author(s):  
A.L. Lancaster ◽  
D.E. Deyton ◽  
C.E. Sams ◽  
C.D. Pless ◽  
D.C. Fare ◽  
...  

Research was conducted to determine if soybean oil sprays may substitute for petroleum oil for control of insects on nursery crops. Dormant field-grown `Globe' arborvitae shrubs infested with Fletcher scale were sprayed on 9 Mar. 1997 with 0%, 2%, 3%, or 4% soybean oil. One hundred scales per plant were evaluated on 4 Apr. 1997. Spraying 2% to 4% soybean oil on dormant arborvitae caused ≥97% mortality of Fletcher scale compared to only 7% mortality on untreated plants. of white pine, viburnum, `Anthony Waterer' spirea, `Green Beauty' boxwood, western red cedar, `Blue Star' juniper, `Blue Pacific' juniper, `Japanese Garden' juniper, and arborvitae plants in trade gallon pots and `Densiformus' yew and dwarf `Alberta' spruce in trade quart pots were sprayed with 0% (water control), 1%, or 2% soybean oil (emulsified with Latron B-1956) or 2% SunSpray Ultra-Fine Spray oil on 26 Aug. 1997 for phytotoxicity evaluation. No phytotoxicity occurred on western cedar, spirea, boxwood, yew, arborvitae, or viburnum. Spraying Sunspray or soybean oil caused initial loss of blue color on blue junipers and white pine. Spraying 1 or 2% soybean oil or 2% SunSpray caused phytotoxicity to `Blue Star' juniper. The `Blue Pacific' juniper, `Japanese Garden' juniper, and Alberta spruce were slightly damaged by 2% but not by 1% soybean oil.


Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 369 ◽  
Author(s):  
Arumugam Saravanan ◽  
Moorthy Maruthapandi ◽  
Poushali Das ◽  
John H. T. Luong ◽  
Aharon Gedanken

Carbon dots (CDs) were obtained from medicinal turmeric leaves (Curcuma longa) by a facile one-step hydrothermal method and evaluated for their bactericidal activities against two gram-negative; Escherichia coli, Klebsiella pneumoniae, and two gram-positive counterparts; Staphylococcus aureus, S. epidermidis. The CDs exhibited spherical shapes with a mean size of 2.6 nm. The fluorescence spectra of CDs revealed intense fluorescence at λex/em = 362/429 nm with a bright blue color in an aqueous solution. The CDs showed strong photostability under various environmental conditions (pH, salt, and UV-radiation). The complete bactericidal potency of CDs was 0.25 mg/mL for E.coli and S. aureus after 8 h of exposure, while for K. pneumoniae, and S. epidermidis, the CDs at 0.5 mg/mL good antibacterial effect within 8 h and complete eradication after 24 h of exposure is observed. The release of reactive oxygen species played a crucial role in the death of the bacterial cell. The present study provides a strategy for the preparation of CDs from a medicinal plant and their potential antibacterial activities against four common contagious pathogens.


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