Rubies from Mozambique – Field report published by GIA

I have had some involvement with mineral projects in Mozambique; I follow with attention news, especially on tantalum, diamonds – Diamonds discovered in Mozambique – Mustang Resources’ Save Project, coal – and rubies – Montepuez’ GEMFIELDS rubi mine – newest updates on the world’s single largest ruby and corundum deposit.

I have just came across an excellent GIA field report on the Mozambican Montepuez ruby mine, originally published at the 2015 Spring issue of GEMS & GEMOLOGY.


Montepuez’ GEMFIELDS rubi mine – newest updates on the world’s single largest ruby and corundum deposit

Discovered in 2009, Montepuez (Mozambique) is the world’s single largest ruby and corundum deposit. GEMFIELDS acquired a 75% interest in the concession in June 2011 from Mwiriti Lda. Montepuez Ruby Mining Lda (“MRM”) is the project operator and a joint venture between Gemfields and Mwiriti Lda. GEMFIEDLS released two documents on Montepuez by SRK Consulting.

According to the Reserves and Resources presentation:

  • 16 million carats (“mct”) produced to date.
  • To date a total of USD55 million has been invested , generating current total revenue of USD122 million.

GEMFIELDS (AIM:GEM) rubies in Mozambique

Mozambique (Moçambique) contains a major gem province, until recently one of the world’s hidden treasures. If their tourmalines and other pegmatite related gems were already famous, ruby emerged as hot news in the last few years, with GEMFIELDS (AIM:GEM) producing mine  in Montepuez (northern Mozambique, Cabo Delgado province) – click here for their concession’s kmz (Google Earth format file shared via a Dropbox link).

In November 2014, Gemfields announced that an exceptional 40.23 carat rough ruby from Montepuez would form part of the December auction. The ruby was successfully sold, with the price remaining undisclosed given the principles on which Gemfields’ auctions are conducted – original statement here, also subject of a previous post in this blog.

Recently (original statement here),

Further to the announcement made on 7 December 2012, Gemfields plc, (AIM: GEM) is pleased to announce the completion of its acquisition of controlling interests in two additional ruby deposits in the Montepuez district of the Cabo Delgado province in Mozambique (the “Megaruma Licences”).

The conditions of the acquisition agreement have now been satisfied and the licences, valid for an initial period of 25 years, were formally issued by the Mozambican government on 22 September 2014 and 12 November 2014 respectively to a new company, Megaruma Mining Limitada (“Megaruma”), in which Gemfields is a 75% shareholder. The two licences, which do not border on one another, each share a boundary with Gemfields’ existing 75% owned Montepuez ruby deposit and cover approximately 19,000 hectares and 15,000 hectares respectively.

Previously, GEMFIELDS Annual Report and Financial Statements 2014 (June 30, 2014) ruby highlights:

Bulk sampling summary for 75% owned Montepuez Ruby Mining Limitada (“Montepuez”) in Mozambique for the year:

  • Approximately 6.5 million carats of ruby and corundum extracted (2013: 1.9 million carats) taking the total ruby and corundum extracted to 8.4 million carats.
  • Rough sales and auctions:
    • First-of-a-kind proprietary grading and sorting framework for rough rubies and corundum was well received at the inaugural auction in Singapore in June 2014;
    • First auction of rough ruby and corundum generated revenues of US$33.5 million at an average realised price of US$18.43 per carat; and
    • Next ruby auction is scheduled to take place before 31 December 2014 – results above.

GEMFIELDS is listed in London’s AIM (AIM:GEM) – check it here. You can also navigate into their website at

Sínese is a Lisbon-based consulting and engineering company specialised in Economic Geology. For further information or advice on mineral projects (Angola, Mozambique, Portugal, Brazil or elsewhere), contact us at or use the contact form.