Magma is the foremost contributor to transporting mass and heat through the Earth's crust and knowledge of its ascent mechanics is of great importance for understanding geological processes. Magma intrusions are linked with resource emplacement, thus intrusion mechanisms has implications for effective resource extraction in e.g. mining, oil and gas drilling. In this thesis I explore the possibilities and challenges in utilizing optical rheometry and velocimetry in couple to observe the stress-strain relationships and deformation features of viscous fingering and hydrofracturing of complex viscoelastic materials as an analog for magma intrusions. With a self-made prototype of the concept I examined the deformation features of a colloidal smectite clay suspension, posing as a host rock analog, intruded with olive oil. The results of the concept conceived are very promising. The use of a polariscope to obtain the birefringence pattern of the flow display a wide variety of features that are invisible to the human eye. The observations include several artifacts with similar appearance as structural geological features. One major implication of this research is the fact that intrusions that look viscous exhibit elastic stress-patterns and fractures when observed through a polariscope. Several prior works need to consider their conclusions on categorization of fracture patterns. This alone proves the validity of the concept. A significant conclusion from the experiments is that the rheological response in a gel matrix subjected to fluid injection is indeed dependent on viscosity ratio. In addition to the observational results, the smectite host rock analog used in the experiments have proved to display a wide range of viscoelastic behaviour. The sample preparation protocol needs to be rigourous to achieve reproducible results, but laponite serves well in modelling viscoelastic deformation.