Winza ruby with hollow tube as a helix
By Dr. Michael S. Krzemnicki, first published in Facette 30 (March 2026)
In late 2007, a new deposit of rubies was discovered near the village of Winza in central Tanzania, creating quite a stir in the trade due to the quality and vivid colour of these rubies. The highest quality Winza rubies were reportedly found in the eluvial soil in the first few months (Schwarz et al., 2008). Further mining of the primary mafic rocks (mainly amphibolite) produced corundum in various colours, but much fewer fine rubies. Following the discovery of significant ruby deposits in Mozambique (initially in Niassa and subsequently near Montepuez, both in the north of the country), most miners left for Mozambique, resulting in the mining activity at Winza practically coming to a halt (Pardieu et al., 2009).
Fine gem-quality Winza rubies have always been rare and sought after by gem collectors, and are now rarely encountered in gemmological laboratories as few stones remain in circulation. Recently, we had the opportunity to analyse an exceptional 10 carat Winza ruby (Figure 1). A well-known and characteristic feature of Winza rubies is the presence of long, curved hollow channels. We were therefore extremely excited to find such a beautiful hollow tube in the shape of a helix in this ruby (Figure 2). This inclusion not only provided evidence of its origin from Winza, but also proved that nature’s art and real beauty are often found within a gemstone.
