Journal de géologie et géophysique
Libre accès

Abstrait

A Review of Gemstone Occurrences, Provenance, and Origins in Nigeria

Juliana Omotayo, Oluwatoyin Ajilore, Temitayo Adeyemi*

Nigeria is the most important producer of gemstones in Western Africa, with commercial deposits of precious and semi-precious stones like Paraiba tourmaline, sapphire, emerald, aquamarine, spessartite, amethyst, zircon, and a few rare species like ruby, phenakite, kunzite, tanzanite, tsavorite, and lepidolite. When cut, faceted, and polished for use in jewellery or other personal adornments, gemstones belong to a particular class of commercial minerals. Nigeria is endowed with significant gemstone resources. Gemstones are minerals that are part of a nation's natural endowment and can be explored, exploited, and the profits can be used for the good of the community. They are also minerals having distinctive physical characteristics such as strong colour, increased specific gravity, high Mohs scale of hardness, perfect cleavage, etc. Nigeria has economic reserves of precious and semi-precious stones in Western Africa. Because of their special qualities, such as their beauty, shine and glitter, gems are charming objects that are coveted by both royalty and the wealthy. In pegmatite veins that are oriented N-S, NE-SW, and occasionally vertical or steeply dipping, in the southwest of Nigeria, gemstone occurrences can be discovered. These veins penetrate older lithology of the schistose, mafic-ultramafic, and migmatite gneiss complex rocks. Tourmaline such as garnet, topaz, and the coloured gemstone tourmaline etc., can be found in pegmatites as single crystals buried in anhedral to euhedral structured crystals, particularly in the weathered kaolinized zones. Many of commercial gemstone deposits in Nigeria are in small pockets of weathered bedrock (pegmatite, granites, and basalts) with associated eluvial and alluvial deposits. Due to their value and part of their rarity, gemstones have a variety of uses, both for consumers and for industries that employ them as raw materials to create products and byproducts made from jewels. The existing, careless method of exploitation generates a lot of trash and does not preserve the environment, artisanal mining and government regulation are urgently required for proper exploitation and management of Gemstones in Nigeria.