Stones worn as pendants, medallions or necklaces play an important protective role for the entire body, stronger even than rings, earrings, brooches, because they are placed on the projection area of the central energetic channel (Sushumna Nadi), where the chakras are located.

Bracelets worn around the left hand (which develops a Yin-type receptive, lunar, feminine polarity) enable the reception of beneficial energies of the universe, whereas if worn on the right hand (which develops a Yang-type solar, masculine, polarity), they enable the transmission of positive, curative energies.

The length of the chain is important.
Crystals hung on a chain at the base of the throat (in which case the pendant sits on the projection area of Vishuddha chakra) bears stronger effects on the communicational, creative plan, offering energy to the entire body and to the entire human aura.
Crystals hung on a chain between throat and heart has beneficial effects on a secret force center (Manas chakra) linked to certain altered stated of consciousness. Crystals placed near the heart (Anahata chakra) impacts stronger the sentimental, spiritual plan.
Crystals placed (in a pocket) right above the heart has stronger effects on the emotional plan.
Crystals should be kept in pouches made of natural fibers. Synthetic materials are contraindicated, since they are detrimental to crystals.

Precious stones characteristic to each astrological sign
ARIES - amethyst, aquamarine, fire agate, aventurine, citrine, rock crystal, coral, diamond, garnet, hematite, jade, kyanite, blood stone (heliotrope), red jasper, Apache tear, white onyx, rhodochrosite, ruby, sardonyx, emerald, spinel
TAURUS - agate, aventurine, carnelian, amber, citrine, coral, chrysocolla, rock crystal, pink quartz, diamond, iolite, jade, red jasper, kunzite, kyanite, lapis lazuli, rhodonite, sapphire, selenite, emerald, blue tourmaline
GEMINI - aquamarine, agate, alexandrite, amethyst, apatite, aventurine, carnelian, celestite, citrine, chrysocolla, chrysoprase, rock crystal, pink quartz, fluorite, garnet, howlite, jade, green obsidian, opal, pearl, sapphire, tanzanite
CANCER - aquamarine, moss agate, aventurine, chalcedony, calcite, carnelian, amber, chrysocolla, rock crystal, fluorite, garnet, opal, black onyx, pearl, moon stone, ruby, emerald
LEO - chalcedony, carnelian, citrine, rock crystal, diamond, garnet, jade, patterned jasper, labradorite, onyx, fire opal, pyrite, rhodochrosite, ruby, sun stone, tourmaline
VIRGO - moss agate, amazonite, amethyst, aventurine, chalcedony, carnelian, citrine, chrysocolla, chrysoprase, rock crystal, smoky quartz, pink quartz, dioptase, garnet, hyacinth, jade, pink jasper, moldavite, blood stone, purple obsidian, snowflake obsidian, onyx, opal, peridote, sapphire, sugilite, tourmaline
LIBRA - amazonite, ametrine, aventurine, citrine, chrysoprase, rock crystal, smoky quartz, pink quartz, diamond, iolite, jade, kyanite, lapis lazuli, lepidolite, malachite, obsidian mahogany, blood stone, onyx, opal, fire opal, peridote, moon stone, sun stone, sapphire, tanzanite, blue tourmaline bleu
SCORPIO - aquamarine, Botswana agate, charoitte, rock crystal, garnet, labradorite, malachite, moldavite, blue-green obsidian, opal, peridote, moon stone, rhodochrosite, ruby, topaz, pink tourmaline, turquoise, unakite
SAGITTARIUS – fire agate amethyst, azurite, chalcedony, charoitte, citrine, chrysocolla, chrysoprase, rock crystal, smoky quartz, dioptase, garnet, iolite, red jasper, labradorite, lapis lazuli, malachite, moldavite, blue / silver / golden obsidian, blood stone (heliotrope), onyx, fire opal, peridote, ruby, sapphire, spinel, topaz, sodalite, tanzanite, pink tourmaline, turquoise
CAPRICORN - agate, amethyst, fluorite, rock crystal, smoky quartz, garnet, jade, blood stone, tiger eye, white onyx, ruby, black tourmaline, turquoise
AQUARIUS - agate, amethyst, amber, rock crystal, fluorite, garnet, hematite, hyacinth, lapis lazuli, hawk eye, opal, sapphire, turquoise, zirconium
PISCIS - aquamarine, blue agate, amethyst, citrine, coral, rock crystal, fluorite, hematite, jade, blood stone, lapis lazuli, opal, fire opal, moon stone, dark flue sapphire, turquoise

Stone specific to each season
SPRING – emerald, amethyst, green diamond, chrysoberyl, pink topaz, peridote
SUMMER – ruby, zirconium, garnet, alexandrite, pink topaz, fire opal
AUTUMN – sapphire, hyacinth (zirconium), topaz, garnet, tourmaline, chrysolite
WINTER – diamond, quartz, white sapphire, turquoise, moon stone, pearl, labradorite

Stone characteristic to each day of the week
MONDAY – moon stone, pearl, rock crystal
TUESDAY – sapphire, ruby, garnet
WEDNESDAY – ruby, amethyst, lapis lazuli
THURSDAY – tiger eye, sapphire
FRIDAY – alexandrite, emerald, jade
SATURDAY – labradorite, turquoise, diamond
SUNDAY – amber, topaz, sun stone