Some basic crystal information about our most commonly used gemstones (for more detailed information see book recommendations and websites below):
What is Mohs Hardness Scale?
Mohs hardness scale is a chart that measures how resistant a gemstone or mineral is to being scratched or damaged when exposed to general wear and tear. The higher the number on the scale, the harder the gemstone is. A diamond for example measures a 10 on the Mohs scale. Mohs hardness scale was developed in the 1800s by German geologist Friedrich Mohs, and is used worldwide to measure the hardness of a mineral. The scale is not exact but is based on the ability of one material (whose hardness is known) to scratch and damage another. For example, if a newly discovered mineral is scratched and damaged by Aquamarine (7.5 – 8 hardness) but not damaged by Carnelian (7 hardness) then its hardness on Mohs scale would fall somewhere between 7 and 7.5. (www.cooksongold.com)
What are crystal systems?
There are six crystal systems. All minerals form crystals in one of these six systems. Although you may have seen more than six shapes of crystals, they’re all variations of one of these six formations. Each system is defined by a combination of three factors:
- How many axes it has.
- The lengths of the axes.
- The angles at which the axes meet.
An axis is a direction between the sides. The shortest one is A. The longest is C. There is a B axis as well and sometimes a D axis.
The six crystal systems are: the isometric system, the tetragonal system, the orthorhombic system, the monoclinic system, the triclinic system, the hexagonal system (which is sometimes divided into hexagonal and a trigonal subsystem).
For a more detailed description and illustrating images go to: https://www.gemsociety.org/article/mineral-habits/
Crystal formation process:
Minerals form in all geologic environments under a wide range of chemical and physical conditions, such as variations in temperature and pressure. The four main categories of mineral formation are:
- igneous, or magmatic, in which minerals crystallize from a melt
- sedimentary, in which minerals are the result of sedimentation, a process whose raw materials are particles from other rocks that have undergone weathering or erosion
- metamorphic, in which new minerals form at the expense of earlier ones owing to the effects of changing, usually increasing temperature or pressure or both on some existingrock type
- hydrothermal, in which minerals arechemically precipitated from hot solutions within
The first three processes generally lead to varieties of rocks in which different mineral grains are closely intergrown in an interlocking fabric. Hydrothermal solutions, and even solutions at very low temperatures (for example groundwater), tend to follow fracture zones in rocks that may provide open spaces for the chemical precipitation of minerals from solution. It is from such open spaces, partially filled by minerals deposited from solutions, that most of the spectacular mineral specimens have been collected. If a mineral that is in the process of growth (as a result of precipitation) is allowed to develop in a free space, it will generally present a well-developed crystal form, which adds to a specimen’s aesthetic beauty. Similarly, geodes which are rounded, hollow, or partially hollow bodies commonly found in limestone, may contain well-formed crystals lining the central cavity. Geodes form as a result of mineral deposition from solutions such as groundwater. (www.brittanica.com)
Gemstones
Amethyst
- Formula: SiO2 with (Al, Ca, Fe, Li, Mg, Na)
- Hardness: 7
- Crystal system: trigonal
- Formation process: igneous
- Chakra: traditionally third eye, crown
The origin of its name lies in the Greek word amethyein – not drunk, giving an indication of one of the attributes of this powerful crystal: the Greeks wore it to wade off negative thoughts, homesickness and drunkenness, which is why wine was often served in amethyst chalices. Amethyst is a wonderfully versatile yet powerful and protective crystal: put it under your pillow against nightmares, place it on your crown to ease headaches, place it around the house or wear it to protect from geopathic stress… Legend has it that amethyst attracts justice and protects against danger. Amethyst is a very positive stone and a natural tranquiliser balancing the mind and calming emotions. Physically amethyst is also a real allrounder with detoxifying, pain relieving, respiratory system supporting, anti-inflammatory and further heling attributes.
Aventurine (green)
- Formula: SiO2 with fuchsite [K(Al, Cr)3Si3O10(OH)2] and other minerals
- Hardness: 6.5 – 7
- Crystal System: trigonal
- Formation process: igneous, sedimentary, or metamorphic
- Chakra: heart
Aventurine is a soothing and positive crystal. It was first discovered in the 18th century and it was named after a green glass, which was created “by chance” (“ a ventura” in Italian) when a worker accidentally dropped some metal shavings into melting glass, creating a beautiful green colour. Most green aventurine is found in India and sometimes therefor referred to as Indian Jade. Aventurine is considered both a physical and emotional healer, nurturing self-love, perseverance and peace of mind and considered a stone of good luck, abundance and growth. Physically this beautiful stone is said to combat infection, balance the nervous system and support detoxification.
Calcite (yellow)
- CaCO3 with iron (Fe)
- Hardness: 3
- Crystal system: trigonal
- Formation process: sedimentary
- Chakra: Sacral chakra, solar plexus
The colour yellow is associated with the air element. The crystal yellow calcite symbolises inner catharsis, expansion and growth. It’s an uplifting stone boosting self-esteem, encouraging expression and it stimulates the higher mind. Physically yellow calcite improves digestion and can help to balance the endocrine system.
Carnelian
- Formula: SiO2 with hematite (Fe2O3)
- Hardness: 7
- Crystal system: trigonal
- Formation process: igneous or sedimentary
- Chakra: sacral chakra, root chakra
Carnelian gets its name from the Latin “corneolus” for cherry. The Egyptians used to carry it as a stone to renew life-force energy and put it into burial sites to protect the deceased on their journey to the afterlife. Hildegard von Bingen already describes its healing attributes in the medieval times. Carnelian is a great mindfulness stone as it grounds you in the present. It’s said to promote courage, vitality, self-confidence and creativity… in other words to light your fire. Physically, carnelian is attributed with the female reproductive organs, it’s beneficial for arthritis and rheumatism (inflammation), regulates bodily fluids and improves the absorption of vitamins and minerals among other things.
Clear quartz
- Formula: SiO2
- Hardness: 7
- Crystal system: trigonal
- Formation process: igneous, sedimentary or metamorphic
- Chakra: universal, traditionally crown chakra
Clear quartz is often referred to as universal healer with references throughout history and cultures: Up to the Middle Ages it was believed to be petrified ice, the emperor Nero used to drink his wine from clear quartz chalices as it was said to quench thirst, Augustus offered the largest clear quartz known at this time to deity and various indigenous tribes place a clear quartz crystal with newborn babies for good luck. Clear quartz is an amplifier and often used in combination with other crystals to magnify the effect.
Dumortierite
- Formula: Al7BO3 (SiO4)3O3
- Hardness: 7
- Crystal system: orthorhombic
- Formation process: igneous
- Chakra: throat, third eye
Dumortierite was named after the French paleontologist Eugène Dumortier (1803-1873) after it was first described in the Rhône-Alpes of France. It is a stone associated with physical pain relief an d disorders of the digestive system. It is said to boost confidence, alleviate fear and anxiety and help embrace stillness, thus classed as a powerful meditation stone.
Heliotrope (bloodstone)
- Formula: SiO2 with hematite (Fe2O3)
- Hardness: 7
- Crystal system: trigonal
- Formation process: igneous
- Chakra: root
The name Heliotrope is made up from the Greek words helios – sun and trepein – to turn and it was often seen as a connection stone between the human and divine. Heliotrope is a stone seen as grounding, strengthening and stabilising. As the name bloodstone suggests it has historically been used to purify and detoxify and even staunch blood flow when used topically. It is said to support the absorption of nutrients and facilitate quick recovery after illness or injury. Heliotrope is a stone of courage and protection, supportive particularly in new life phases and endeavours.
Kambaba jasper
- Formula: SiO2 + Fe, O, OH, Si
- Hardness: 6.5-7
- Crystal system: trigonal
- Formation process: sedimentary
- Chakra: heart
Kambaba jasper, also sometimes referred to as crocodile jasper, was formed by microorganisms over three billion years ago. These microorganisms: cyanobacteria/blue-green algae are believed to have been responsible for the creation of the earth’s oxygen atmosphere. Kambaba jasper is a profoundly earthing stone, giving stability and balance harmonizing us with the cycles of the natural world, attuning us to the planet’s biorhythm and connecting us to Mother Earth at the deepest level. Kambaba jasper supports our metabolism, both with detoxification and assimilation of vitamins and minerals and it is beneficial to assist in unblocking energy in the meridian system.
Lapis Lazuli
- Hardness: 5.5
- Crystal system: cubic and trigonal
- Formation process: metamorphic
- Chakra: heart, throat, third eye
- Formula: Lazurite (Na, Ca)8(Al, Si)12(S, SO4) with pyrite (FeS2) and calcite (Ca, CO3)
Lapis Lazuli has a long history of being a very revered and treasured stone and its name is a combination of the Arabic word “Azul” – blue sky, and the Latin word “Lapis – stone. In Egypt Lapis Lazuli was one of the most precious crystals, which can be seen in famous artefacts such as Tutanchamun’s Death Mask for example. Napoleon and the Sun King Louis XIV were also great admirers of this gem. Lapis has always played a big role as a pigment in art and many famous murals and paintings display the incredible depth of colour in the robes of the Madonna and other prominent Saints and Aristocrats. It symbolises wisdom and inspiration and is also known as the friendship stone. Lapis Lazuli is a very uplifting and protective stone, that is often used against depression, supporting a positive mindset. It can be helpful to relieve pain and is immune strengthening among other healing attributes.
Leopardskin jasper
- Formula: SiO2
- Hardness: 7
- Crystal system: trigonal
- Formation process: igneous
Chakra: root chakra, solar plexus
This beautiful stone is found in Australia, Mexico and South Africa. Especially in indigenous cultures of North, Middle and South America the leopardskin jasper played a big role. Mexico was often seen as the middle of the earth, where leopardskin jasper is found, so it was believed that our planet was built from this stone. This crystal was both seen as a protective stone against predatory animals as well as a mineral to harmonise the relationship between humans and the animal kingdom, but also between humans and the whole environment. Leopardskin jasper is great to support organs of elimination and supports detoxification. It relieves nausea and pains in the lower abdomen. It has a calming effect boosting stamina, resistance and creativity and supports overall health and well-being.
Magnesite
- Formula: MgCO3
- Hardness: 3.5 -4.5
- Crystal system: trigonal
- Formation process: metamorphic
- Chakra: third eye, heart
Raw magnesite resembles a brain shape pointing towards its powerful effect on the mind, balancing the hemispheres of the brain and supporting new ways of thinking. Magnesite is a great meditation stone inducing deep peace and relaxation and particularly beneficial for opening the heart chakra during loving kindness meditation. Physically magnesite is associated with relieving gastrointestinal symptoms and as a general relaxant.
Moonstone
- Formula: KAlSi3O8
- Hardness: 6-6.5
- Crystal system: triclinic
- Formation process: igneous
- Chakra: sacral chakra, third eye chakra, crown chakra
Moonstone is a “female” stone of love, fertility and natural cycles closely associated with the moon and moon cycle. It’s a very calming, balancing and empathic stone and is said to be a great emotional healer. Physically moonstone is associated with the elimination of toxins, balancing of hormones and assimilation of nutrients among other things.
Moss Agate
- Formula: SiO2 with hornblende (Ca, Na) 2–3 (Mg, Fe, Al)8O22(OH, F)2
- Hardness: 6.5 – 7
- Crystal System: trigonal
- Formation process: igneous
- Chakra: root, heart
Moss Agate is not banded, and therefore not strictly an Agate in scientific terms; but is included in the Agate family. Agate is a variety of Chalcedony, a mineral of the Quartz family. It is clear to milky white, with dendritic inclusions of manganese or iron that has grown into patterns similar to moss or lichen. Throughout history and all cultures, Moss Agate has been known as the crystal of gardeners and agriculture. It was considered a miraculous healing stone and was used as a talisman to make warriors strong and victorious. Moss agate is a stone of growth, both literally in plants and crops as well as personal growth. It’s a balancing and harmonising crystal for physical and emotional health known to regulate the cardiovascular system, soothe skin irritations and infections as well as gastrointestinal symptoms.
Ocean jasper
- Formula: SiO2
- Hardness: 7
- Crystal system: trigonal
- Formation process: igneous
- Chakra: root, solar plexus, heart, throat
As the name suggests this beautifully patterned stone is often associated with the ocean, in myths particularly with Atlantis. Ocean jasper is another fantastic allrounder. It’s a very positive and uplifting crystal alleviating stress, balancing emotions and encouraging a generally patient and positive outlook on life. Ocean jasper is very versatile healer on a physical level with anti-inflammatory, circulatory system and immune boosting properties.
Red jasper
- Formula: SiO2
- Hardness: 7
- Crystal system: trigonal
- Formation process: sedimentary or igneous
- Chakra: root chakra
Red jasper is a beautifully grounding stone associated with our root chakra, the chakra connecting us to the earth. It is mentioned as a sexual energising stone in ancient Egypt, as the God-given Stone in the bible to use as the corner stone to build a new Jerusalem, and legend has it that red jasper embellished dragon slayer Siegfried’s sword. This crystal is a stone of courage and determination transmuting negative energy and protecting against electromagnetic and environmental pollution.
Rose Quartz
- Formula: SiO2 with trace minerals
- Hardness: 7
- Crystal System: trigonal
- Formation process: igneous
- Chakra: heart
Rose quartz beads dated as far back as 7000BC have been found in Mesopotamia, known as Iraq today. The Assyrians and the Romans were known as the first to use rose quartz in jewellery with many powers assigned to the pink crystal, including magic properties, anti-aging, protection etc. Medical practitioners in the Middle Ages started to use the quartz in healing potions, among them the famous Abbess Hildegard von Bingen. In many cultures rose quartz was and still is associated with the heart, both physically and emotionally. It promotes love, self-love, forgiveness, compassion and helps heart connection especially for people who have difficulties expressing emotions. Rose quartz is a calming and relaxing stone often worn as jewellery or simply as a pocket stone.
Sodalite
- Formula: Na8Al6Si6O24Cl2
- Hardness: 5.5-6
- Crystal system: cubic
- Formation process: igneous or metamorphic
- Chakra: throat, third eye
Sodalite is often attributed to the water element as it helps to regulate the bodily fluids through support of the lymphatic system. It’s often used for conditions of the throat and larynx and is said to support skeletal health. Sodalite is a beautiful, empowering crystal supporting free expression and bringing clarity and clear perception. This crystal is also often associated with nonjudgement, supporting one of the basic principles of mindfulness.
Stichtite (Atlantisite)
- Formula: Mg6Cr3+2(OH)16[CO3] · 4H2O
- Hardness: 1.5 – 2
- Crystal system: trigonal
- Formation process: stichtite is derived from the chromite by hydrothermal metamorphism, the details of the formation process are still discussed in the literature.
- Chakra: heart, third eye, crown
Stichtite (Atlantisite) was discovered in 1910 in Dundas, Tasmania, Australia by A.S. Wesley, chemical expert with the Mt Lyell Copper Mine, it was named after Robert Carl Sticht, the manager of the mine. This stunning rare mineral is said to promote inner peace, self-love and acceptance, decision making and energy flow. It has been used to provide pain relief and stabilise blood pressure.
Stromatolite
- Formula: SiO2Fe2+CaCO3
- Hardness: 4-7
- Chakra: earth star, root, heart, sacral
Stromatolite (Greek for layered rock) has organic origins and was formed by microorganism in lime, the fossilised organic sediment showing in the wavelike pattern of the stone, which were created through the movement of ocean water. Stromatolite is said to hold the ancient original earth energies as it was formed by the first lifeforms on our planet, and as that it is considered one of the most powerful earth and nature connecting stones.
Sunstone
- Formula: (Na,Ca)Al(Si,Al)Si2O8 (oligoclase) or K(AlSi3O8) (microcline) with inclusions of hematite (Fe2O3) or copper (Cu)
- Hardness: 6-6.5
- Crystal system: triclinic
- Formation process: igneous or metamorphic
- Chakra: Solar Plexus, sacral chakra
In ancient Greece this beautiful stone was aptly dedicated to Helios, the sun god, believing that it will protect the earth and keep the sun on the right path. Sunstone is a joyful, harmonising stone, excellent to support the flow of energy. It’s a source of positivity counteracting depression, pessimism and low self-esteem. Sunstone literally brings in the light, warmth and shining powers of the sun into physical and emotional healing, promoting positive interactions, healthy boundaries and a generally happy and peaceful outlook on life.
Tiger’s eye
- Formula: SiO2 with crocidolite [Na2 (Fe2+3Fe3+2) Si8O22(OH)2] and iron (Fe)
- Hardness: 7
- Crystal system: trigonal
- Formation process: sedimentary
- Chakra: solar plexus, third eye
Tiger’s eye got its name from its appearance, which when polished resembles the feline eye, it is not known though who actually coined the name. In many cultures tiger’s eye was worn as a protective talisman, it carries the energies of both earth and sun which makes it a balancing stone said to help with making healthy decisions and weighing up the options. Tiger’s eye is often associated with ocular health and it represents truth, justice, prosperity and abundance.
Tree agate
- Formula: SiO2 with manganese oxide or iron oxide.
- Hardness: 6.5-7
- Crystal system: trigonal
- Formation process: igneous
- Chakra: root chakra, heart chakra
In parts of India this stunning agate is used and known as a talisman and in Christianity this crystal is frequently used in combination with clear quartz in rosary beads to deepen a meditative state. Tree agate is a very gentle, rooting and harmonising stone which is very soothing for the nervous system and promotes inner peace. It’s also a crystal that promotes earth and environmental healing and can be placed into plant pots to protect and boost the plants’ vitality. Tree agate is the perfect stone to connect to the natural world spiritually, mentally and emotionally.
Recommendations for further reading:
Crystal Basics by Nicholas Pearson
Crystal Bible, 1, 2, 3 by Judy Hall
The Encyclopedia of Crystals by Judy Hall
Rock On by Kate Mantello
