Prospecting using ultra-violet radiation

In a method of prospecting for minerals which luminesce when exposed to ultra-violet light, a hole is formed in the body to be prospected and an ultra-violet radiation source is inserted into the hole. The depth of insertion is measured, and for each depth of insertion, any luminescence is detected. An apparatus for carrying out the method has an ultra-violet radiation source which can be lowered into a preformed hole in the body. The depth of insertion of the source into the hole can be measured, for instance by means of a graduated rod to the end of which the source is attached. Any luminescence is detected by means of, for instance, a photo-detector, or a system of mirrors, or light sensitive film. Selective prospecting for minerals which luminesce when exposed to ultraviolet radiation and which occur in places where other minerals, which also luminesce, are present is also possible. Use can be made of filters which allow the passage of a certain ultra-violet frequency only, or which allow the passage of a certain luminescent frequency only