Petrographical study of the Lakadong Limestone member of Shella Formation (Jaintia Group) was carried out for identification of different constituents, mineralogical classifications and to decipher depositional environment. The limestone includes fossils, pellets, odites and intraclasts as allochem microcrystalline calcite and sparry calcite. The limestone is represented as sparry allochemical limestone and biogenic pellet limestone. This biogenic rock contains more than 3.1 pellet ratio. Hence it is also known as Biosparrude. In physical character, limestone is mostly packstone and boundstone types. Moreover, non-ferroan calcite is dominant in the limestone.

The process of cementation consists of chemical deposition of sparry calcite. Both equigranular and inequigranular fabrics are present in the limestone. The major diagenetic processes worked on the limestone include solution, cementation, neomorphism and pressure solution. Strained calcite, vein, vug, stylolite are the notable microstructure present in the limestone. In the limestone, aggrading neomorphism is common.

The petrographic studies indicate that deposition of carbonate sediments took place in a quiet water marine basin (lagoon type).