Its not a stupid question :). Crystals have a natural vibration to them. Which are used for a huge variety of things, some not even associated with spells or healing. Like quartz watches and electronics...
Crystals, have been used for centuries as source for attuning your chakras and aiding in meditation. Each type of crystal has a different use and natural power to it.
The skull has power if you give it power. I think if its adorned with the crystal as a necklace, it is probably just a trinket.
But, if it were me, i would cleanse it with sea salt and re-charge the crystal at the next full moon and with your positive energy to be on the safe side.
Good luck on your new journey... :)
I'm sure everyone has a different opinion and ritual when it comes to cleansing, so just know that my suggestion works for me.
To cleanse the crystal I'll place it in a bowl of sea salt. (some use salt water, but i find just the salt works just as well)
I'll leave it in the bowl over night. The following morning I'll rinse it with purified or spring water.
To re-charge with positive energy I'll place my stones in the sunlight. Unless, there is a full moon then I'll put them out overnight in the moonlight. I'm usually more energized by the sun (but that's just me!).
Some will use smudge sticks (sage) or incense to cleanse stones. Again, I believe its just preference.
Good luck! :)
One warning though! Not all crystals react well to sea salt, so research alternative methods of cleansing as well as the basic structure of the crystal before using it. Salt water is fine for most members of the quartz family, but it breaks down some other crystals.
Also, never cleanse amethyst with sunlight. It dulls the color and actually sucks the energy out instead (for future reference).
It seems to me that the skull itself if just a simple object. What you put into it; your energy, intent, etc. -- that is what makes the difference between 'good' and 'bad'.
