AI Appraisal Estimate

This specimen is a large, rough-cut chunk of raw black tourmaline, also known as schorl. Measuring approximately two to three inches in diameter, the piece displays a deep, opaque jet-black color with a glassy to sub-metallic luster on its structural faces. The crystal exhibits its characteristic trigonal system features, most notably the heavy vertical striations and furrowed texture along the elongated prism faces. One side shows a more fractured, conchoidal surface where it likely broke away from its matrix. There are visible inclusions of a tan or light-colored host rock or sandy mineral matter trapped within the crevices and on the exterior pockets, which is common for natural specimens gathered directly from earth deposits. The edges are sharp and irregular, showing no signs of synthetic tumbling or polishing. Its dense, heavy appearance and lack of transparency are hallmark quality indicators for high-iron tourmaline. The specimen appears to be in its natural geological state with no visible repairs, showing typical weathering and minor abrasions consistent with raw mineral extraction.

I have carefully examined the provided visual documentation of this raw black tourmaline (schorl) specimen. The item measures 2-3 inches and presents classic mineralogical features, including heavy vertical striations and a trigonal crystal habit. Based on the deep opaque jet-black coloration and sub-metallic luster, this appears to be a genuine high-iron specimen. The condition is consistent with 'natural rough,' featuring typical conchoidal fracturing and legitimate host-rock inclusions in the crevices. There is no evidence of heat treatment or synthetic polishing, which preserves its value as a geological sample. Currently, the market for raw schorl is robust due to its popularity in both metaphysical and mineral collecting circles. However, because schorl is one of the most abundant forms of tourmaline globally, it is not considered rare. Comparables for unmounted specimens of this size and quality typically retail in the $40 to $70 range depending on the specific gravity and clarity of the striations. The lack of a matrix or unique crystal terminations (ends) prevents it from reaching the higher 'museum-grade' collector price points. A primary limitation of this appraisal is the inability to perform a specific gravity test or streak test via image alone, which would definitively rule out similar-looking minerals like ilmenite or black kyanite. For a certified authentication, I would require an in-person examination to verify the hardness (7.0-7.5 on the Mohs scale) and inspect the specimen under short-wave ultraviolet light to check for diagnostic fluorescence in the associated matrix material.