Mozambique produces the majority of
the rubies used in joaillerie and high joaillerie. This is especially true for stones
weighing two carats or more; for the time being, Myanmar is the leading producer of
rubies in small sizes. Until recently, Mozambique's ruby production was very
traditional. However, towards the end of 2012, the government wanted to solve this by
granting a mining corporation a concession over the Namanhumbir deposit in the country's
northeast. This extremely prospective deposit spans over 30,000 hectares. When nature is
kind, we get highly crystalline rubies that are deep red and slightly orangey.
Mozambican rubies are typically purplish red to red in color, with some
stones exhibiting an orange tint. The color intensity ranges from delicate pink
sapphires to bright red rubies. Gem corundum has the following standard gemological
properties: a refractive index between 1.760 and 1.768 (+/– 0.001), birefringence of
0.008–0.009, and a specific gravity average of 3.98–4.00. Fluorescence can range from
strong to medium red in long-wave UV radiation and from medium to faint red in
short-wave UV radiation.
Particles are the most prevalent type of inclusion.
These oriented needles and particles frequently form in bands that follow the corundum
development structure. Maninge Nice–type rubies frequently have these entire hexagonal
shapes. Mugloto-type rubies rarely have a whole hexagonal outline, but instead feature
straight or angular bands of particles.
The inclusions in both varieties of
Mozambican ruby are the identical, although their quantity differs. Mugloto rubies have
fewer mineral crystals than Maninge Nice rubies. Maninge Nice rubies exhibit more
cracks, which can be attributed to their position in a primary or near-primary
deposit.