Lapis Lazuli

Overview

Lapis lazuli is a metamorphic rock composed primarily of lazurite (the mineral that provides the blue colour), calcite (white), and pyrite (gold metallic flecks). It has been prized since antiquity. Ancient Egyptians used it in jewellery and ground it into ultramarine pigment. The finest lapis combines deep, even blue colour with sparse, well-distributed pyrite inclusions and minimal white calcite.

Physical Properties

Mohs hardness: 5 to 6. Specific gravity: 2.38 to 2.45. Because lapis is a rock rather than a single mineral, its properties vary with composition. Higher lazurite content produces better colour and slightly higher specific gravity.

Colour and Quality

The finest lapis shows a uniform, deep "royal blue" colour without visible white calcite patches. Scattered gold pyrite inclusions are considered attractive and authentic by most buyers, though some prefer a completely uniform blue. Heavy white veining significantly reduces value. The colour should be natural; dyed lapis is common in the low-end market and can be detected by wiping with acetone (which removes dye).

Major Sources

Afghanistan (Badakhshan Province): The Sar-e-Sang mines have produced the world's finest lapis lazuli for over 6,000 years. Afghan lapis sets the standard for colour and quality. Chile produces commercial-grade lapis, often lighter in colour. Russia (Lake Baikal area), Pakistan, and Myanmar also yield lapis of varying quality.

Historical Significance

Lapis lazuli was one of the most traded gemstones of the ancient world. It was carved into cylinder seals in Mesopotamia, ground into eye shadow in Egypt, and traded along the Silk Road to China. Medieval European painters ground Afghan lapis into ultramarine pigment, the most expensive paint colour of the era, more valuable than gold leaf.