0.25 Ct. Alexandrite from Ceylon (Sri Lanka)

This exquisite transparent 0.25 carat marquise shape alexandrite measures 5.66 x 2.77 x 2.41 mm, and it is an exceptional small gem for a collector or for a refined jewelry commission. The stone is cut as a mixed brilliant, a choice that balances scintillation from brilliant facets with the color distribution benefits of a mixed pavilion. At a clarity grade recorded as very very slightly included when evaluated at eye level, the view is remarkably clean for practical wear, with inclusions that do not distract from the gem at normal viewing distances. Color intensity is medium, which in an alexandrite is often more desirable than overly saturated material because it allows the characteristic color change to read clearly in both lighting environments. The polish is excellent, and crucially the stone has received no enhancement, preserving its natural optical character. Origin is Ceylon Sri Lanka, a source known for producing alexandrite with pleasing green to pinkish transitions, and this provenance adds to the gemological story of the piece. For those considering mounting, the marquise outline will present elegant finger coverage and will visually appear larger than many round stones of equivalent weight, an important consideration for design and value per visual impact.

From a gemological perspective this alexandrite stands apart because alexandrite is one of the rare gems that displays a true color change, a phenomenon caused by trace chromium substituting in the chrysoberyl structure, interacting with different light spectra to yield distinctly greenish tones in daylight and pinkish to red tones under incandescent light. Chrysoberyl varieties such as alexandrite have a refractive index roughly in the range 1.74 to 1.76 and dispersion on the order of 0.014, which yields lively brilliance and crisp facet reflections without the high fire seen in diamond. For comparison, diamond has a refractive index near 2.42 and dispersion near 0.044 yielding more fire, while corundum species such as sapphire and ruby have refractive indices close to 1.76 and dispersion near 0.018, providing strong brilliance but not the unique spectral shift of alexandrite. Emerald and other beryl group gems have lower refractive indices near 1.57 and therefore show less brilliance. What makes this alexandrite more desirable to an educated buyer is that it combines very good optical performance, a clean eye level clarity, and an authentic color change, a combination that is rarer than simply high brilliance alone.

When advising clients I emphasize practical considerations that enhance enjoyment and preserve value, and The Natural Gemstone Company stands behind the natural provenance and untreated status of this stone. To observe the color change at its best view the gem in strong natural daylight or a daylight balanced light source near 6500 K to see the greenish side, and view under incandescent or warm LED light around 2700 K to reveal the pinkish tones, as lighting will dramatically affect the perceived hue and saturation. The mixed brilliant marquise cut will maximize return of light and distribute the color change along the length of the stone, which works beautifully in east west settings, halo rings, and fine pendant designs that allow light from multiple angles. For care avoid harsh ultrasonic cleaning given the stone shape and check settings periodically to protect the pointed ends of the marquise, and obtain a formal assessment or report if provenance or grading is needed for insurance or resale. For collectors who appreciate scarcity and optical intrigue this 0.25 carat Ceylon alexandrite delivers a compact, durable, and eye catching example of the species, and The Natural Gemstone Company is available to provide additional images, light views, or certification options to support a confident purchase.