There are a few ways of looking at Hot Stone Massage and how it is so powerful when it comes to releasing and relaxing a tired and stressed mindbody, and I will start with the geography.
Bassalt stone, the smooth black stones used in this practice, are created when magma errupting from the earths core is supercooled very quickly in the oceans into which it seeps. Some practitioners perfer mined and evenly cut stones as they can give a more predictable heat release rate, but I prefer mine that have all been either river tumbled and polished in Peru (where my larger stones come from), or sea tumbled and polished (as many of my smaller stones have been). The stones have a very low chrystaline content (no time for minerals or other elements to get into the rock before it sets), so it maintains heat better than any other rock, then releases it evenly.
Energetically, the stones are a gift from the core of the earth, mother earths warm and loving heart so to speak. So using them on the body is akin to having a hug from the heart of the earth! The stones I use have all experienced many hundreds if not thousands of years of movement and friction. They have been thrown around by the tides and currents and bashed against eacother and everything they come into contact with - and it has softend away any sharp edges, leaving a smooth surface that clients describe as feeling soft, despite it clearly being an intensely solid hard rock. The energy of the life that has shaped the stones is vital and passes into you. It could be argued that without a crystal element, that there is little crystal therapy in them, but that isnt true. The energy is pure and gounding, without grounding and connection to our earth, there can be no healing in any modality.
And finally, pratically, the heat of the stones that are warmed in a water bath (just like a slow cooker, only mine is 17 liters!), penitrates the body, gently increasing blood flow through the tissues. This influx of blood delivers much needed nutrients and supports detoxification, as well as enabling cellular hydration - critical to fascial health. This means that muscles that are themselves hard a rock need much less pressure to soften and relax.
As with all my sessions, I rarely use just one modality, but a blend of a few to create the optimal outcome. In hot weather, it is wise to discuss with me if you want the stones as it is not always advisable and also makes the therapy room overheat very quickly, so I dont usually put the stones on to heat. They take about 45 minutes to warm, so if you particullaly want them, its always worth making a specific request.