Crystals can be used in spell bottles/bags, spells, rituals, in your bath/shower (if they are not damaged by water), next to your bed, under your pillow, in strategic areas in your home or in a tea bag/receptacle in your teapot or water bottle (so that it lends energy to your drink - please don’t swallow or eat your crystals!).
Crystals can also adorn your magical tools or act like talismans in jewelry. You can also just pop them into your pockets (or, if you're a lady, your bra), you don’t necessarily have to wear them to reap the benefits of their energy.
For beautification or health effects, you can use them in a face roller, a gua sha stone or during massage.
Some examples of Crystals and their correspondences are below. It is worth noting that some come in various colours as well as shapes;
Agate
Healing, wealth, protection, insight - this comes in various colours
Amber
Protection, healing, luck, magic amplifier (see below)
Amethyst
Happiness, dreaming, psychic enhancer, mental clarity
Aventurine
Perception, luck, money (see below)
Bloodstone
Strength, courage, victor, healing (see below)
Carnelian
Vitality, health, protection, confidence, mental clarity, ambition, energy
Chalcedony
Banishes nightmares, peace, mental balance (see below)
Chrysoprase
Success, luck, happiness, friendship
Citrine
Dreaming, protection, psychic enhancer, abundance, joy, positivity (see below)
Coral
Power, healing, protection
Diamond
Peace, loyalty, harmony, energy source, banishing
Emerald
Mental power, money, love, banish illusions, divination clarity
Garnet
Strength, healing, protection
Hematite
Divination, grounding, concentration
Jade
Longevity, wisdom, healing, weather magic, good luck, abundance
Jasper
Tenacity, protection, dispels hostile magic and spirits
Jet
Divination, shielding, protection
Lapis Lazuli
Love, healing, protection (see below)
Moonstone
Dream control, astral control, divination, psychic enhancer
Obsidian
Focus, clarity, contemplation, logic
Onyx
Balancing sex drive, protection, counter-magic
Opal
Power, astral protection, luck, scrying
Pearl
Wealth, Good fortune, love
Clear Quartz
Mental clarity, focus, emotional stability, psychic enhancer, master healing stone (see below)
Rose quartz
Love, compassion, relationships (see below)
Ruby
Power, wealth, vitality, protection, clarity, focus
Tiger’s Eye
Courage, protection, energy, abundance, safe travels ( see below)
Topaz
Wealth, healing, love, protection, happiness
Tourmaline
Business, relationships, friendships, love
Turquoise
Money, courage, friendship, love, protection