Segmentation by type classifies the market into powder, single‑crystal, and thin‑film forms, each fulfilling distinct process and performance criteria. Powder, typically supplied as high‑purity granules for subsequent crystal growth, represents the largest share (≈55 %) because it underpins both bulk crystal manufacturing and additive‑manufacturing routes, offering flexibility in impurity control. Single‑crystal CsI, grown via the Bridgman or Czochralski methods, comprises about 35 % of sales, prized for its uniform lattice structure that minimizes scattering losses in high‑resolution detector arrays. Thin‑film variants, deposited through vapor‑phase or sputtering techniques, occupy the remaining 10 %, catering to compact photodetector modules and integrated sensor platforms where form‑factor and substrate compatibility are paramount. This type‑level taxonomy elucidates how material form influences supply‑chain logistics, cost structures, and end‑use performance, thereby informing strategic positioning for manufacturers within the Ultrapure Grade Cesium Iodide market.