Kornerupine

Carat weight is a major factor because facetable kornerupine crystals are uncommon. Small stones under 1 carat exist, but clean, well-colored gems above 2–3 carats are scarce and attract significant collector premiums. Very large, fine stones are rare.

Color is critical. The most prized kornerupine displays vivid, medium to medium-dark green to blue-green hues with strong saturation and attractive pleochroic effects. Brownish, grayish or very dark stones are less desirable, though some collectors appreciate unusual color ranges. Pleochroism means cutters must choose the orientation that yields the best face-up color.

Because kornerupine often contains inclusions and internal fractures, eye-clean or nearly eye-clean stones are relatively rare and more valuable, especially in larger sizes. Prominent fractures and heavy inclusions reduce transparency and durability.

Cutting is crucial to balance pleochroism, tone and brilliance. Well-proportioned mixed cuts oriented to the most attractive color direction can yield lively stones. Poor orientation may produce overly dark or dull face-up colors, undermining the gem's potential.

Kornerupine occurs in metamorphic rocks and skarns in localities such as Sri Lanka, Tanzania, Madagascar, Myanmar and others. Gem-quality material suitable for faceting is rare, and production from most deposits is sporadic and small-scale.

Demand is driven primarily by advanced collectors and specialized colored-stone dealers who appreciate its rarity, pleochroism and rich colors. It is seldom encountered in mainstream retail, though interest has grown as information about rare gem species spreads.

Recent Trends: niche but stable collector interest, with fine, well-documented stones achieving strong prices through specialist dealers and auctions.