subcrystalline
/ˌsʌbˈkrɪstəlʌɪn/ /ˌsʌbˈkrɪst(ə)lʌɪn/Chiefly Geology
adjective
Chiefly of rocks and other natural materials: imperfectly or incompletely crystalline; semi-crystalline.
Origin
Early 19th century; earliest use found in Curtis's Botanical Magazine. From sub- + crystalline.