Chips of glass are investigated using a number of different techniques. Using a refractive index involves investigating the glass's light bending ability because different types of glass bend light at different angles. Glass will change its refractive index when heated and allows for this clue to be measured. The technique used involves measuring the refraction when the sample is immersed in heated oil, used as a agent to prevent the sample from being destroyed under direct high temperatures. Once heated at the correct temperature, a laser is then used to measure the light refraction.

When testing the density of a sample of glass, investigators compare the glass in two different liquids which both have individual identities. Glass floats in dense, heavier liquid whereas it sinks in lighter, less-dense liquid. The investigators combine the liquids until the glass neither floats nor sinks, but sits halfway in the liquid formula. The density of the glass is then worked out using proportions of the two types of liquid. If no match between a piece of glass found on a suspect and a sample found at the crime scene is apparent, investigators consult a database of glass types which can tell if the glass sample is common, rare or unusual.

Glass fibres can reveal what object that they were applied into i.e. the use for which they were manufactured -a good example is if the glass fibres occur in layers, they are usually used to strengthen structures made out of plastic, such as the hull of a boat. Glass fibres are identified by their point of melting, optical aspects such as their refractive index, their shape and appearance underneath a microscope and using chemical analysis.

Animal fur is significantly finer than the hair of a human and is different between certain species. Most forms of animal hair are covered in scales, which also makes it very distinguishable from human hair. Synthetic fibres are also relatively less distinctive compared to natural fibres when studied underneath a microscope.