Hematita Alexandrite
Hematita Alexandrite
Finest-quality colour-change chrysoberyl from Minas Gerais, Brazil
Hematita alexandrite refers to colour-change chrysoberyl recovered from the Hematita deposit in the state of Minas Gerais, Brazil, first discovered in 1987. The material is widely regarded as among the finest alexandrite produced outside the historic Russian Ural Mountain localities, distinguished by a strong and well-defined colour change from bluish-green in daylight to purplish-red under incandescent light. The deposit's relatively brief productive period and subsequent depletion have elevated Hematita stones to the status of collector and investment-grade gems, with fine examples commanding prices that rival, and occasionally exceed, those of comparable Ural material on the international market.
Geological Setting and Discovery
The Hematita deposit lies within the Itabira region of Minas Gerais, a state long celebrated for its extraordinary mineralogical wealth, including world-class tourmaline, topaz, aquamarine, and chrysoberyl. The alexandrite-bearing pegmatites of the region are associated with the same Precambrian metamorphic and granitic terranes that host much of Brazil's gem production. The deposit was discovered in 1987 and entered commercial production shortly thereafter, attracting immediate international attention as soon as the quality of the colour change became apparent to the trade. Active mining was intensive but geologically constrained; the deposit proved relatively shallow and limited in extent, and significant production had largely ceased within roughly a decade, though small quantities of material have continued to surface intermittently from residual workings and secondary alluvial concentrations.
Gemmological Characteristics
As a variety of chrysoberyl — the mineral species BeAl2O4 — Hematita alexandrite shares the fundamental physical and optical constants of the species. Hardness is 8.5 on the Mohs scale, with an orthorhombic crystal system and a refractive index range of approximately 1.746–1.763, yielding a birefringence of around 0.009. Specific gravity is typically 3.71–3.75. The colour-change phenomenon arises from the presence of chromium as the principal chromophore, which creates a transmission window that straddles the boundary between the green and red regions of the visible spectrum, making the perceived hue highly sensitive to the spectral composition of the illuminating light source.
In Hematita stones of fine quality, the daylight colour is typically described as a medium to strong bluish-green or teal, shifting cleanly to a purplish-red or raspberry-red under incandescent or candlelight conditions. The completeness and saturation of this shift — often assessed on a scale from weak to strong — is the single most important quality determinant for alexandrite, and Hematita material at its best demonstrates a shift that gemmologists and traders characterise as complete or near-complete, meaning that neither residual green persists in incandescent light nor residual red in daylight. This quality of shift is what invites comparison with the most celebrated Ural stones, though Hematita alexandrites are generally perceived as having a slightly more bluish (rather than pure green) daylight appearance and a slightly more purplish (rather than pure red) incandescent appearance relative to the finest Ural specimens.
Clarity in Hematita material is variable. Many stones contain inclusions typical of pegmatite-grown chrysoberyl — fine needles, partially healed fractures, and occasional two-phase inclusions — though eye-clean to near-eye-clean examples are known and command strong premiums. Crystal habit is typically tabular to short prismatic, and twinning, common in chrysoberyl generally, is observed in some Hematita rough.
Comparison with Russian and Other Origins
The benchmark against which all alexandrite origins are measured remains the historic Ural Mountain deposits of Russia, principally the Tokovaya River area in the Sverdlovsk Oblast, where alexandrite was first identified in the 1830s. Classic Ural alexandrite is characterised by a pure grass-green to emerald-green daylight colour shifting to a raspberry-red or pigeon-blood-red under incandescent light, with relatively high transparency and a colour change of exceptional completeness. Fine Ural material is now exceedingly rare on the market, and most specimens in circulation originate from antique jewellery or old collections.
Hematita alexandrite occupies a position immediately below the finest Ural material in the hierarchy of origins as understood by the specialist trade, and above the other significant Brazilian localities — notably Malacacheta and Carnaíba — as well as most material from Sri Lanka, Zimbabwe (Sandawana), Tanzania, and India. Sri Lankan alexandrite, while sometimes large and well-formed, typically exhibits a less saturated colour change, shifting from yellowish-green to brownish-red. Indian alexandrite from Andhra Pradesh can show strong colour change but often with a more muted overall saturation. Zimbabwean material from the Sandawana Valley is notable for its intense green but tends to occur in small sizes. Hematita stones combine strong saturation, a pleasing daylight hue, and a relatively clean shift, making them the preferred Brazilian origin for connoisseurs.
Treatment and Enhancement
Alexandrite as a species is not routinely subjected to the heat treatment or fracture-filling processes common in corundum or emerald. Hematita alexandrite is generally traded as unenhanced material, and no widely documented treatment specific to this origin has been established in the gemmological literature. Buyers of significant stones should nonetheless seek laboratory reports from recognised gemmological laboratories — such as the Gübelin Gem Lab, SSEF, GIA, or Lotus Gemology — which can confirm origin and assess enhancement status. Origin determination for alexandrite has become increasingly sophisticated, with laboratories drawing on trace-element chemistry (measured by LA-ICP-MS) and inclusion fingerprinting to distinguish Hematita material from other Brazilian localities and from non-Brazilian sources.
Market and Collecting Context
The depletion of the Hematita deposit has had a direct and well-documented effect on the market for its stones. As with any exhausted gem locality of recognised quality — Paraíba tourmaline from the original Batalha mine in Rio Grande do Norte being the most celebrated parallel — scarcity has amplified desirability. Fine Hematita alexandrites of one carat and above with strong, complete colour change and good clarity are infrequently offered at auction or through specialist dealers, and when they do appear, they attract competitive bidding from collectors focused on Brazilian gem history as well as from generalist alexandrite collectors. Prices per carat for top-quality Hematita stones in the range of two to five carats are broadly comparable to those of equivalent Sri Lankan material and approach those of fine Ural stones, though the Ural premium for truly exceptional specimens remains intact.
Provenance documentation — including original rough photographs, dealer chain-of-custody records, and early laboratory reports — adds meaningful value to Hematita alexandrites, as it does for other historically significant locality gems. The 1987 discovery date means that some stones have a traceable modern collecting history, and a number of notable Hematita specimens have passed through major auction houses in New York, Geneva, and Hong Kong.
Within Brazil, the Hematita deposit holds a place of particular significance in the national gem narrative, representing the moment when Brazilian alexandrite achieved international recognition as a world-class product rather than a secondary substitute for Russian material. The deposit's legacy continues to influence how Brazilian chrysoberyl is marketed and valued, and it has encouraged systematic prospecting for alexandrite across Minas Gerais and neighbouring states, with modest new discoveries reported periodically, though none yet matching Hematita in quality or scale.