The body surface of Spongilla alba is typically smooth but may feature irregular projections. These sponges form massive growths of moderate thickness. The oscula, which are moderate to large in size, are not very conspicuous. The dermal membrane adheres closely to the symplasm, resulting in a hard but brittle consistency. The coloration of Spongilla alba ranges from pale gray to off-white. The megascleres are feebly curved, ranging from slender to stout and fusiform. Those with pointed ends (amphioxea) appear smooth, with dimensions spanning from 0.26-0.33 mm in length and 12-19 µm in width. The dermal membrane bears numerous slightly curved, slender microscleres, specifically amphioxea with erected spines. These spines are more prominent and longer in the central region, often featuring knob-like inflations at their tips. The dimensions of these microscleres range from 0.06-0.12 mm in length and 2-4 µm in width. The spicules of the gemmule (gemmoscleres) are feebly curved, slender, and covered with large recurved spines, which are more numerous at the tips. The length and width of these gemmoscleres range from 0.08-0.11 mm and 5-8 µm, respectively.