Sharpening grit is a maker's label for how coarse or fine an abrasive is, given as a number, a word or both. Buck's 2026 catalog pairs numbers with words, including 325 (Coarse), 750 (Medium) and 1200 (Fine). The cited Case Arkansas-stone entries use grade words without numbers. Buck also prints a number for its own natural Soft Arkansas stone.
Buck prints grit as a number with a word in parentheses. Its 2026 catalog lists "325 (Coarse) 750 (Medium) 1200 (Fine)" for the EdgeTek Ultra FlipStik, lowest number at Coarse and highest at Fine, and "400 (Medium)" for Buck's Diamond Pocket Sharpener, so Medium sits on two numbers inside one maker's table. Kershaw's FAQ gives its Ultra-Tek a "600-grit diamond sharpening surface", a number with no word beside it. A word such as Medium therefore needs its product context; it is not a shared number across all sharpeners.
The cited Case Arkansas-stone and Aluminum Oxide Oilstone pages use grade words without grit numbers. Case's EZ-Hone page describes grades from coarse to extra fine, its Bench-Top page calls Soft Arkansas medium-grade, and its Aluminum Oxide Oilstone page calls that stone fine-grade. Those descriptions apply to those products, rather than establishing a rule for every Case sharpener.
Natural Arkansas stones carry grade names such as Soft and Hard. The cited Case Arkansas-stone and Aluminum Oxide entries use words alone. For its own Soft Arkansas stone, Buck's 2026 catalog lists "500-600 (Course)", a figure for that Buck stone and no other, yet the third stage of Buck's how-to page, fine sharpening, names natural stone as one of its two tools.
Soft against Hard gets its own comparison in soft vs hard Arkansas stone, and how many grits one kit needs is argued in do you need different grits for sharpening.