Amber: Split Or Fake?

[NZ_Fossil_Collecta]

i have a piece of amber, it has a dark split along the top, and a ridge of darker material inside it descending from the split. the split also has a dent on it directly above an insect in the amber (it is a common insect) and along the split is also a miniature flower or seed and some unknown debris. the bottom of the ridge of darker material is irregular and wavy, and the insect has clearly been through decomposition due to a decomposition bubble on it's abdomen. here is a picture, if anyone could identify whether it is a fake or not that woould be great. it was fairly cheap but then again it is not a rare insect and amber size is very small (1/2 size of my thumb nail) here is a picture if anyone can tell whether it is a drill job or a natural cause.

[NZ_Fossil_Collecta]

p.s even holding it in my hand the darker material is VERY obvious.