Isabel dos Santos exonerada da Presidência da SONANGOL

De acordo com notícias publicadas há minutos, Isabel dos Santos, filha do ex-Presidente de Angola, foi exonerada da Presidência da SONANGOL.

Isabel dos Santos é substituída no cargo por Carlos Saturnino, que ocupava o lugar de Secretário de Estado dos Petróleos no Governo Angolano.





One decade of ups and downs in rough and cut diamonds

Quarterly Zimnisky Rough Index.png


The last two decades have been a carrousel of emotions in the mining industry:

  • Oil and gold prices had steadily been growing since 2001. Oil spiked to maximum historical values in 2008 (and then crashed, to climb again for 3 consecutive years, plateau for 4 years, until mid 2014, crashing again, reaching nominal values of 2005, and recovering marginally since then).
  • Gold has had a more regular pattern, growing since to 2001 until 2011, maintaining a high plateau until the end of 2012, crashing until mid 2013, becoming relatively stable since then.
  • Polished diamonds have shown a much less volatile behaviour, with some ups in 2008 and 2011 (mimicking the markets’ general mood) but rapidly stabilising into a nominal stability (a slow real price decline).
  • Rough diamonds prices rose roughly 50% in nominal terms (as measured by the Zimnisky Rough Index) since 2007, a more subdued increase in real terms. The price increased in the 2009 – 2011 period, after which it stabilised until early 2015, after which it slowly declined until today.

Why are diamond prices less volatile than other mineral commodities’?
Why do rough and polished prices behave differently?
New deposits discovery and production capacity expansion seem increasingly difficult; why don’t diamond prices increase significantly in real terms?
Are there two different markets in diamonds?
What is the impact of new recovery technologies (XRT) in diamond markets?

Will discuss that in the next post. What is your opinion?

The oil and gold indices were calculated by just dividing the monthly gold average nominal price in US dollars by their price (nominal US dollars) in January 1980.

The Antwerp Diamond Index is a set of indices used to measure the price variation of five types of polished diamonds. The index is based on prices in US $ and gives the average price evolution on the Antwerp market of diamonds ranging in colour from exceptional white + to white and in clarity from LC to VS2:

  • 1 ct diamonds (1973 =100)
  • 1/2 ct diamonds (1973 =100)
  • A = Small Brilliant (1980 =100)
  • B = Melée (1980 =100)
  • C = 1/4 ct diamonds (1980 =100)

The Antwerp Diamond Index is maintained by the Diamond Office of The Antwerp World Diamond Centre (AWDC). To know more about AWDC and the Diamond Office , just visit their website:

The Zimnisky Global Rough Diamond Price Index was created to consolidate rough diamond price information and publish current respective price changes of rough diamonds on a weekly basis in the form of an index.  The intent of the Index is to track, analyze, and disseminate current aggregate rough diamond price fluctuations for use by a range of diamond industry participants.

The proprietary index methodology primarily incorporates price data from rough diamond transactions in the primary market, e.g. sales via long-term contract, tender, and auction by commercial miners. The Index also includes a minor sensitivity to polished diamond prices, given that miners utilize the polished market as a factor when determining contract pricing of rough. In addition, the Index includes a minor sensitivity to stand-alone diamond mining equities, as the relative liquidity that equities provide can imply the current profitability and revenue generation ability of diamond miners, which is directly influenced by the current rough diamond market.

Given the nature of natural diamond production, the variance in quality of stones produced, or the product mix, can impact global rough diamond prices on an average price-per-carat basis. The Index strives to represent as accurately as possible current price changes reflected in the average rough diamond transaction valued on a per carat basis in U.S. dollars. The Index value does not directly represent the price of a 1-carat rough diamond, but the percentage change in the average value of a rough diamond transaction relative to the initial Index value, at a given point in time.

The Index is based on an initial value of 100 using data starting on April 4, 2004. The Index is updated on a weekly basis, typically on Saturday. Retroactive revisions to index data are made on a quarterly basis typically after public miners release official quarterly sales figures.
(adapted from

To know more about the Zimnisky Global Rough Diamond Price Index, or obtain Paul Zimnisky’s insight on the diamond markets, check

Oil and metals: Goliath and David

Another excellent infographic published by Visual Capitalist (a few weeks ago).
They left diamonds out of the picture, a pity. They included graphite, diamond’s darker and duller brother, though; curiously enough, both markets are very similar in value (diamond production marginally smaller, at close to $14B).
Courtesy of: Visual Capitalist

350 Angolan kwanza (AOA) for one dollar (USD) is now the informal rate

With plummeting oil prices and an oil based economy, the Angolan currency has further lost its value, now with a street value of 350 kwanza (AOA) for one dollar (USD). The informal (street) value is now half of the official rate (itself well bellow last year’s value).

The challenges for the Angolan Government are always big in a country needing growth and stability; now they have become bigger, with inflation and loss of fiscal revenues. Notwithstanding the difficulties, Angola never lost its optimism even in (much more) difficult times – with creativity and hard work this will be only a temporary crisis.

Angolan currency looses value (- 37%) in the last year

The Angolan currency (Kwanza- Kz) lost 37% of its value (in USD) as a result of last year’s crude oil price crash. A carbon-dependent economy (with oil and diamonds being, by far, the country’s largest exports), Angola was hard hit by the evolution of oil prices in the international markets.

One USD was worth Kz 135,968 – average oficial interbank exchange rate in the period of 14 to 16 September 2015, compared to Kz 99 around one year ago. The informal (street) exchange rate reaches values over Kz 200 – Agência Lusa values cited here.

The impact in daily life is felt through increased inflation. International money transfers have also been affected.

In an ironical twist, with crashing international oil prices resulting in plummeting fiscal income, the Angolan Government was forced to cancel fuel subsidies, increasing gas prices at the pumps. In addition to escalating transportation costs, increasing fuel prices are especially grievous as virtually any house in Angola depends on generators for electricity, at least as a (frequently needed) backup to the public grid (unavailable in many regions or unreliable at best). This counter-intuitive effect compounded the inflation generated by the deteriorated exchange rate.

You may read more on this subject in this article (Portuguese).

Mineral commodities 2013 total mined volumes and values, average prices

Commodities 2013

Diamonds mined in 2013 total 14 bn USD. How do they compare with other mineral commodities?

Rather than using somebody else’s compilations, I prefer to check values published by (commodity) specialised international organisations or public companies (OPEC, World Gold Council, KPCS, USGS, etc.). After some work, I have arrived to the estimates presented in the table to the left.

Is the ranking surprising? Any obvious error on the table’s values? Comments and suggestions (always) welcome. Yes, reality changed a lot since 2013 (only 18 months ago).