Gemstones have long been associated with particular traits or benefits that they bring to the wearer.
Here is a brief guide to aid you in your choice.

Gemstone Colour Properties
Agate Various A harmonising stone to soothe the mind & aid concentration.
Amethyst Purple Imparts clarity of mind & aids decision making. Cleanses the blood & encourages restful sleep.
Aquamarine

Pale Green

A stone of courage, said to reduce stress & calm the mind. Traditionally carried by sailors to promote safe travel on water.
Blue Lace Agate Pale Blue Cooling, calming & healing, particularly for the throat.
Citrine

Pale Amber

Brings a sense of balance & wellbeing, heightened logic & intuition. Said to attract wealth.
Emerald Green Enhances unity, loyalty & faithfulness in love & friendship. Brings wisdom & broadens vision.
Garnet Dark Red Inspires love & devotion. A stone of commitment & fidelity.
Hematite Dark Grey Dissolves negativity & gives psychological strength to overcome addiction. Strengthens relationships. Aids circulatory problems & stimulates absorbtion of iron. 
Jasper Various A strong, nurturing, stable stone that encourages determination & independance.
Kyanite Blue/Grey A tranquil stone said to restore energy balance.
Labradorite Grey/Iridescent Mystical & spiritual stone that heightens intuition & brings clarity of thought. Regulates metabolism.
Moonstone White/Rainbow Stone of new beginnings, assisting in fertility, conception, pregnancy & childbirth. Soothes stress & aids insomnia.
Onyx Black Gives strength & self-protection from negativity or unhealthy relationships. Supports teeth & bones.
Opal White/Grey Associated with love & passion, a symbol of faithfulness. Aids depression & eye problems.
Pearl White/Various A symbol of purity & innocence. Symbolises faith, truth & honesty. Linked to marriage.
Peridot Green A powerful cleanser, said to aid detoxification & heal tissue. Balances negative emotion & relieves depression.
Rose Quartz Pale Pink For unconditional love & infinite peace.
Sardonyx Black/Brown/Cream Promotes happiness, strength & stability in marriages & relationships.
Smoky Quartz Brown/Grey A protective, grounding stone to promote positive thought & insightfulness. Said to aid abdominal pain & boost fertility.
Tiger Eye Brown/Amber Used as a protective stone that enhances luck & prosperity. Promotes positivity & the ability to recognise one's strengths.
Turquoise Turquoise A healing stone to dispel negative energy & encourage inner calm. Detoxifys & relieves pollutants & infections.