The Mining Commission has issued new indicative prices for coloured gemstones produced in mainland Tanzania, providing updated valuation benchmarks for minerals ranging from emeralds and rubies to garnets, spinels and opals.
The price guide, which became effective in October 2026, sets values based on gemstone quality, size and characteristics, with the aim of supporting mineral assessment and valuation in line with prevailing local and international market conditions.
According to the commission, the prices are determined using the four key gemstone characteristics – colour, cut, carat and clarity (4Cs) – assessed by qualified gemologists.
The guide provides separate valuations for good-to-fine, commercial and industrial grades, with prices varying depending on the gemstone's quality, weight and whether it is sold in rough or cut-and-polished form.
The new benchmarks highlight the substantial differences in value between gemstone categories, particularly for high-quality emeralds, rubies and other precious stones.
Emeralds are among the most highly valued minerals in the guide. Cut-and-polished stones weighing between 0.50 and 0.99 carats are valued at between USD165 and USD1,100 per carat, depending on quality.
For emeralds weighing between one and 1.99 carats, the indicative prices range from USD300 to USD2,000 per carat, while stones weighing five carats or more can fetch up to USD5,000 per carat in the highest quality category.
Rubies also feature prominently, with prices reflecting differences in size and quality.
The guide places cut-and-polished rubies weighing between 0.50 and 0.99 carats at between USD21 and USD888 per carat.
Those weighing between one and 2.99 carats are valued at between USD25 and USD2,797 per carat.
For larger stones weighing between five and 7.99 carats, indicative prices rise to between USD86 and USD8,354 per carat.
The commission has also recognised the distinct characteristics of gemstones from specific mining areas, including emeralds from Sumbawanga and rubies from Morogoro, Mahenge and Mundarara, which have separate entries in the valuation guide.
Other notable gemstones covered include alexandrite, tsavorite garnet, blue spinel, aquamarine, precious opal and tourmaline.
Alexandrite, for example, has an indicative price of up to USD2,756 per carat for cut-and-polished stones weighing between one and 1.99 carats. Stones weighing five carats or more are valued at up to USD5,088 per carat.
Tsavorite garnet, another valuable variety, is priced at up to USD3,600 per carat for cut-and-polished stones weighing 10 carats or more.
Beyond high-value gemstones, the guide covers a broad range of minerals, including quartz varieties such as amethyst, citrine, agate and chalcedony, as well as feldspar, fluorite, diopside and malachite.
For rough gemstones and industrial-grade minerals, prices are also provided per gramme, kilogramme or tonne, depending on the mineral and its commercial classification.
The publication is part of the Mining Commission's statutory responsibility to establish indicative mineral prices using domestic and international market references for assessment and valuation purposes.
The updated guide is expected to provide a common reference for mineral valuation, particularly in transactions involving different gemstone qualities and sizes.
However, the listed figures are indicative rather than guaranteed selling prices. The actual value of an individual gemstone depends on its grading, physical characteristics and prevailing market conditions.
The full October 2026 coloured gemstones price guide is available on the Mining Commission's website at www.tumemadini.go.tz.