Every stone has a natural relation to humans. Here’s a broad classification. It is important to know that it differs from person to person.
Aries: Emerald
Pieces: Diamond
Leo: Blue Sapphire
Gemini: Coral
Aquarius: Ruby
Capricorn: Ruby
Virgo: Ruby
Cancer: Ruby
Scorpio: Emerald
Sagittarius: Diamond
Taurus: Yellow Sapphire
Libra: Yellow Sapphire
EMERALD: Skin, lungs, business, reasoning powers
YELLOW SAPPHIRE: Memory, gynaecological disorders, weight, justice, rage, diabetes
RUBY: Heart, bones, blood count, gynaecological disorders, skin
BLUE SAPPHIRE: Nervous system, uterine trouble, arthritis
DIAMOND: Water content and retention, beauty, blood count, money
CORAL: Energy, epilepsy, calcium in the body, menstrual disorders
PEARL: Mental abilities, rage, positive thinking, insomnia, attention span, blood pressure, excitability