Oct 4, 20232 min read

Unearthing Tanzania's Rare Gemstones: A Mining Adventure to Explore Umba Sapphires and Garnets

Updated: Jan 15

I’ve just returned from Tanzania, where I attended a 17-day adventure tour, unearthing Tanzania's rare gemstones. Hosted by Swiss jeweller Hubert Heldner and organised by his Tanzanian wife and gemstone cutter / instructor, Noreen Masaki, the tour comprised a small group of 12 intrepid travellers: a few professional jewellers, gem cutters, geologists, and a few gemmologists like myself.

We also had three very experienced drivers. When I think back to some of the places we visited that were completely off the beaten track, this was just as well because getting to them was quite a treacherous challenge and it was a minor miracle that we made it.

A full day’s driving from Dar es Salaam, Umba (north of Tanga) was our first stop. We spent five sweltering days mining garnets and sapphires. We each employed two miners to do our digging. Some were local miners and some were Masai – both men and women.

You may think that having others to do the heavy-duty work for you sounds lazy but trust me, it was necessary and totally ethical. Firstly, the income enables the miners to feed and support their families and secondly, their knowledge and mining experience was priceless. Their stamina was phenomenal, digging a hundred times faster than I could ever have! There wasn’t any blood but there was definitely sweat! I just waited until the stones were ready to be sorted.

Most of us are familiar with sapphires – Kate, the Princess of Wales, wears the engagement ring that famously once belonged to Diana, Princess of Wales. (The stunning 12 carat, cornflower-blue sapphire was presented to her by Prince William in 2010.) Princess Eugenie’s engagement ring is also a sapphire – a delicately beautiful, peach-coloured padparadscha.

But would you recognise a sapphire before it was cut and polished and turned into jewellery?

It took a while before I could confidently recognise a raw sapphire. Garnets were easier to spot, usually colourful Rhodolite and Malaya garnets.

I eventually came away with fifty to sixty garnets, black tourmaline and an extraordinary number of different size sapphires, none of which were transparent or of usable quality. Disappointing, but it made me really appreciate just how difficult and rare it is to find a good quality gemstone.

Here are some photos I took of the miners hard at work, digging furiously in the scorching heat of the day, stopping only a few times for a glug of water.