Be prepared to reverse the process using the blue shades so as not to over stimulate the inner powers of spirit. Most human forms are unable to identify their personal pattern or energy vibration's geometry, so you may use simple forms that feel harmonious to the meditator. See this as a form of telecommunication or travel from old. If the power of the gem is needful, its power can be given by transferring some of the energy into another object. Wear the scarf, being aware of the transfer on energy.
Rule of thumb is that the clearer and more compressed the stone, the stronger the energy.
If combining stones, great thought and knowledge must be used to understand the purpose of such combinations. As the yellow sacred stones are so powerful, be aware of this and use it for greater purpose. You may recognise this through a slightly different syntax. Interestingly, I get nothing. I am not really sure on that one.