Diamond miner Lucapa today showed off a 43-carat yellow gem dug up in its Angola “Lulo” mine.

The stone is “the largest coloured gem-quality diamond recovered to date from Lulo, surpassing the 39 carat pink recovered in September 2016”, Lucapa told investors.

Natural coloured diamonds are very rare — about one out of every 10,000 carats. However yellows are the most common, making up about 60 per cent of all coloured diamonds.

A 116 carat low-quality diamond was also recovered.

“It is the 10th 100-plus carat diamond recovered to date from Lulo and the second 100-plus carat recovered within the first three weeks of 2018,” reported Lucapa (ASX:LOM).

The finds weren’t enough to support Lucapa’s share price however. The stock fell 2 per cent to 25c on Wednesday, valuing the company at about $100 million.

Polished diamond prices continued a downward trend in 2016-17, “reflecting soft consumer demand for diamond jewellery across key markets”, according to Bain & Company’s annual diamond report released last month.

Lucapa Diamond shares over the past year. Source: Investing.com

Global sales of diamond jewellery were “roughly stable”, held back by flat sales in the US — the world’s biggest market.

The outlook was “stable across the different segments of the value chain”, but the industry faced “three key, persistent challenges” according to Bain:

  • Soft demand for diamond jewellery driven by competition from other luxury goods and experiences
  • A “mounting risk” that lab-grown diamonds will legally or illegally erode the market share of natural diamonds
  • The financial stability of diamond players amid price volatility.