Chalcedony

Physical Properties

Chalcedony is a microcrystalline variety of the quartz family.
Chemical composition: Silicon dioxide.
Crystal structure: Trigonal.
Hardness: 7

Metaphysical Properties and Crystal Healing

Blue chalcedony promotes optimism and goodwill. Helps in relieving depression and promotes mental stability. It is believed to calm the nervous system and release worry. Blue Chalcedony is the stone of writers. Chakras: throat (5), third eye (6).

In Astrology

Chalcedony is associated with the star sign Taurus. The famous mineralogist George Frederick Kunz in his 20th century book 'The Curious Lore of Precious Stones' associated it with the three planets MERCURY, JUPITER and SATURN according to its colour.

7 Chakras

Blue chalcedony - Ajna, The Third Eye Chakra ( 6 ) and Vishuddha, the Throat Chakra ( 5 )
Pink and/or green Chalcedony - Anahata, the Heart Chakra ( 4 )
Violet or Purple Chalcedony - Sahasrara, the Crown Chakra ( 7 )