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Minerals and metals are crucial raw materials for industries and a major source of development for the country. In India there has been a pronounced growth in the exploration for minerals both in terms of quantity and value. To further enhance the growth rate and remove any bottleneck, the government has taken several legislative reforms through more transparency and non-discretion by way of first-come, first-served basis in the allocation of mineral concessions, through Mines and Minerals (Development and Regulation) (MMDR) Amendment Act, 2015. Recently, MMDR Act, 1957 has been amended through the Mines and Minerals (Development and Regulation) Amendment Act, 2021 vide notification dated 28.03.2021 for improving ease of doing mineral production and business in the country and help increase Gross Domestic Product (GDP). Exploration of energy-critical minerals, fertilizer minerals, precious metals and stones, strategic minerals and deep-seated minerals which are otherwise difficult to access and for which the country is mainly dependent on imports, needs to be prioritized. Enhanced exploration and mining can significantly reduce India's import dependence on mineral and metals and help economic growth. For comparison, only 10% of obvious geological potential (OGP) area of India has been explored while Australia has explored more than 90% of its area. In this paper, some of these legislative reforms and challenges to provide an impetus to mineral exploration are discussed. [ABSTRACT FROM AUTHOR]

Spectroscopic and microstructural studies of ruby variety corundum samples of Sinapalli, Odisha have been carried out using various physical techniques. FTIR, Micro Raman, photoluminescence along with microstructural and energy dispersive x-ray spectroscopy (EDAX) data reveal presence of hydroxylated form of alumina on the surface with presence of Cr chromophores. These gemstones contain zircon and rutile inclusions. Upon heat treatment, the colour of the ruby variety of gemstones improved by dissolving rutile inclusion inside the corundum lattice. Detailed data of the both untreated and heat treated samples are discussed in this paper. [ABSTRACT FROM AUTHOR]

Emerald, the green gem variety of beryl (Be3Al2Si6O18), is the third most valuable gemstone after diamond and ruby. The green colour appearance of the crystal is due to trace of Cr3+ and V3+, which replaces Al3+ ions in the crystal lattice of beryl. The hue of green colour of emerald depends on the quantity of Cr3+ and V3+ present in the crystal. Be is incorporated along with Cr and/or V during the process of crystallization. Since Be is relatively rare in the upper continental crust, therefore specific geological and geochemical parameters are required for Be to be incorporated in the crystal lattice of emerald.The present work was carried out to understand the lithological and structural control of emerald occurrences in and around Gurabanda area within the Singhbhum shear zone (SSZ) of Singhbhum crustal province, eastern India. The biotite and serpentine schist belong to the Paleoproterozoic Dhanjori Group and constitute the major lithology of the area. Pegmatite and biotite schist contains a variety of gem minerals in abundance in the area and the gem quality emerald occur at the contact zone of quartz vein and mica-schist. Lithology and structure are the main controlling factors of gem-mineralization in the study area. The study indicates that regional metamorphism and deformation processes along the shear zone played a significant role in the formation of emerald deposits. It is inferred that Singhbhum shear zone facilitated a favourable condition, where the Be bearing pegmatites interacted with Cr bearing mica schist or ultramafic rocks to produce emerald crystal. [ABSTRACT FROM AUTHOR]

We report newly obtained U-Pb SHRIMP ages of detrital zircons from metagreywackes in the Hiriyur Formation (Chitradurga Group, Dharwar Supergroup) from the central eastern part of the Chitradurga greenstone belt. U-Pb analyses yield three major Neoarchean age populations ranging from 2.70-2.54 Ga with some minor age population of Mesoarchean. The maximum age of deposition is constrained by the youngest detrital zircon population at 2546 Ma. This is the first report of the occurrence of supracrustal rocks less than 2.58 Ga in the central part of Chitradurga greenstone belt. Close evaluation of detrital ages with the published ages of surrounding igneous rocks suggest that the youngest detrital zircons might be derived from rocks of the Eastern Dharwar craton and the inferred docking of the western and eastern Dharwar cratons happened prior to the deposition of the Hiriyur Formation. The Chitradurga shear zone, dividing the Dharwar craton into western and eastern blocks, probably developed after the deposition. Furthermore, the lower intercept is interpreted as evidence for the Pan-African overprints in the study area. [ABSTRACT FROM AUTHOR]