Lapis Lazuli is an incredibly rare gemstone. Its chemical composition is so complex that the geological conditions have to be just right for its formation. For this reason, lapis lazuli is mainly found in two places on Earth – Afghanistan and Chile. These are the only mines where commercial-grade lapis lazuli is extracted.
There are several other places where you can find some pockets of smaller and lower-quality lapis lazuli – Lake Baikal in Russia and Baffin Island in Canada – but this lapis is too poor to be used in most manufacturing. There are accounts of lapis lazuli occurring in other sites, but these are not confirmed by geologists. Just because there is a blue stone does not make it lapis lazuli.
The Afghan and Chilean deposits, despite being halfway across the world from each other, share some unique attributes that lay the groundwork for high-quality lapis lazuli.
The Afghan deposit, named Sar-E-Sang, is located to the north alongside the Hindukush mountain range. It is at an altitude of 4,000 meters. It is one of the oldest mine in the world, dating back over 7,000 years, and having been the source of lapis lazuli throughout ancient times. The mine is high up in the mountains, covered in snow for much of the year and reaches scorching temperatures during the summer. The area is sparcely populated and inhabited by wild animals, including wolves. Unfortunately, the flow of lapis lazuli from this region has thinned over the years due to the political instability in Afghanistan.
The Chilean deposit is named Flor de Los Andes and is located in Ovalle, about 400 km north from Santiago. It is at an altitude of 3,600 meters in the Andes. The deposit was discovered in 1850, but it was not commercially exploited until a century later in 1950. Unlike the Afghan mine, until recently the Chilean mine has been highly exploited. Chilean lapis lazuli is equally high-grade and the most available on the market.
Despite the fact that both types of lapis are equally high quality, the gemstones have some differences. Afghan lapis lazuli has an intense blue color with gold flecks, but is nearly absent of any of the white or grey streaks that characterizes Chilean lapis. In fact, the deep blue of Afghan lapis is occasionally lightly violet, because it has a higher consistency of the blue-violet lazurite to make up for other substances like calcite.
Chilean lapis lazuli has less pyrite than its Afghan counterpart, giving it less of a bronze tinge. It does have a fair amount of white veins, which alters the color of the stone. Chilean lapis can be as deep as Afghan lapis, but can also look clearer and more translucent if the particular rock has more veins.
In any case, the purity of the stone is not affected by the amount of pyrite, calcite, or any other chemical. In fact, it is these chemical impurities that add to the beauty of the stone.
Golden flecks of pyrite often conjure an image of a starry night sky, while white veins often give the stone a whimsical quality or give the appearance of wisps of cloud streaking the sky. Though lapis lazuli can withstand these small changes in chemical composition, it is clear that its composition is so complex that it is unlikely to occur anywhere else in the world. This makes it a very unique semi-precious stone.