bot·ry·oi·dal 
(bŏt′rē-oidl) also bot·ry·oid (bŏtrē-oid′)
(bŏt′rē-oidl) also bot·ry·oid (bŏtrē-oid′)adj.
Shaped like a bunch of grapes. Used especially of mineral formations: botryoidal hematite.
[From Greek botruoeidēs : botrus, bunch of grapes + -oeidēs, -oid.]
bot′ry·oidal·ly adv.