Fibrous metallic mineral specimen, consistent with stibnite or schorl

This specimen presents a elongated, highly fibrous, metallic structure with a silvery-grey to dark steel luster. The texture appears coarse with deep, parallel longitudinal striations running along the length of the rock or mineral body. The overall morphology is consistent with certain fibrous or acicular metallic minerals, such as stibnite (antimony trisulfide) or possibly a highly metallic/silvery variant of tourmaline (schorl), though physical testing (such as streak test, hardness test, and specific gravity measurement) would be required for a formal geological identification. The surface exhibits small scattered inclusions or pitting and natural crystalline irregularities typical of unrefined mineral formations. No visible labels, stamps, or maker's marks are present. The specimen is held in human fingers, providing a scale indicating a length of several inches.

Based on what I can see in the provided image, this specimen displays an elongated, fibrous to acicular crystalline habit with a metallic, steel-grey luster and pronounced longitudinal striations. The visual characteristics are consistent with minerals such as stibnite or possibly a metallic variety of schorl tourmaline. However, I cannot verify the exact mineral species from a photograph alone. A conclusive identification would require physical inspection and testing, such as evaluating hardness, streak, specific gravity, or performing X-ray diffraction. Assuming the specimen is stibnite of this size (approximately 3 to 4 inches in length) and display quality, the estimated fair market value falls within the $40 to $80 range. Smaller to mid-sized mineral hand specimens of this nature enjoy steady demand among educational collectors, rockhounds, and mineral enthusiasts. The value is driven by the integrity of the crystal formation, luster, and overall aesthetic appeal. Visual surface pitting and minor termination wear typical of natural extraction are present, which are factored into this valuation. Should in-person testing reveal the specimen to be a more common mineral or a less sought-after material, the market value would likely adjust downward to $10–$20. Conversely, if it is authenticated as a high-purity stibnite specimen with undamaged crystal terminations from a notable, well-documented locality (such as the Ichinokawa mine in Japan or specific Chinese deposits), its value could increase significantly with proper provenance documentation. For formal mineralogical classification, an in-person examination by a professional geologist or mineralogist is recommended.