While there is no such thing as the ‘perfect’ stone set, most general sets contain under 50 stones. There are other, specialty sets, which may be different based on the type of massage that is being given. Examples of this are a facial, manicure / pedicure or reflexology set, which will have fewer stones than a full body set. Also, for the therapist who needs to be portable, they will bring a scaled down set to minimize the weight that they have to carry, and usually a Vulsini heating bag.
Ideally, each set will be chosen by the practitioner once they get a feel for what sizes and shapes, they prefer working with. When choosing stones - dark, smooth rounded stones are ideal, with specific shapes and sizes for different body parts (i.e. extra-large placement stones for the belly or sacral area, or flat, rounded stones for work in the scapular region). Effleurage stones will be chosen depending upon the practitioner's preference and hand size.
Size - some practitioners find they like to work with larger stones, as they distribute more heat to the client and have a greater overall effect. Others find the larger stones too cumbersome to use, and prefer working with smaller, more manageable stones. Either method works well, however smaller stones will need to be rotated more often as they lose heat more quickly than the larger ones. Shape - again, practitioner preference prevails as some people prefer flatter stones, and others, more rounded stones.
The stone shape can add to its functionality by conforming to the body part - i.e.: triangle shaped placement stone for the solar plexus and sacrum. We find flatter stones lose heat more quickly, so the preference is to use fuller or thicker ones if possible. Spinal, or Back Layout Stones are flat, and can be quite thick as they will sink into the massage table, however the thickness should be consistent, so the client is comfortable.
Hand placement, or Palm Stones are quite round and allow the fingers to rest comfortably around the stone. Toe Stones, or toe cozies are very thin to fit properly, while Facial Stones and Chakra Stones are flat, so they don't roll off the body. Belly and Sacrum Stones tend to be large, flat, and somewhat rounded. Usually, they are also heavy since they cover such a significant amount of area. These stones are what we call ‘placement’ stones, in that they are put in place and left there for significant amounts of time. It is due to this that these stones are never placed directly on the skin. Place a sheet or towel between the stone and the clients skin, inquire as to your client’s comfort level, and keep a watchful eye for any irritation to the skin in that area.