Spinel

Spinel — Colour, Brilliance and a Mineral with Its Own Identity

Spinel is a gemstone in the spinel mineral group, found in red, pink, orange, purple, blue and black. Its range of colours offers a choice between a strong presence and a more delicate shade.

Despite its possible resemblance to ruby, spinel is a separate mineral with a different chemical composition and crystal structure.

Gemological Properties

Property	Information
Mineral	Spinel
Mineral group	Spinel group
Main chemical composition	Magnesium aluminium oxide — MgAl₂O₄
Colours	Red, pink, orange, purple, blue and black
Hardness	8 on the Mohs scale
Typical refractive index	Approximately 1.718
Typical specific gravity	Approximately 3.60
Crystal system	Cubic
Birefringence	Normally absent, consistent with the cubic structure

These are reference values; the composition of an individual stone may influence its properties.

What Gives Spinel Its Colour?

Trace elements influence colour. Chromium is associated with red and pink shades; iron can contribute to purple and blue colours, while cobalt can produce vivid blue.

Not every blue spinel owes its colour to cobalt. Colour alone is insufficient to establish a stone’s composition.

The Stone Once Mistaken for Ruby

For centuries, red spinels were sometimes identified as rubies. A famous example is the Black Prince’s Ruby in the British Imperial State Crown, which is actually a red spinel.

Quality, Cutting and Price

Colour, clarity, cut and weight influence value. A well-proportioned cut can give spinel considerable brilliance, while prominent inclusions may reduce its value.

Stones of similar weight can differ greatly in quality and price.

Treatments and Synthetic Spinel

It should not be assumed that every spinel is untreated. Heat treatment and fracture filling are known, as are cobalt or nickel diffusion treatments to change colour. Known treatments should be disclosed when describing the stone.

Synthetic spinel, grown in a laboratory, also exists. Professional identification aims to distinguish natural stones, synthetic stones and imitations, and to examine signs of treatment.

Setting and Care

Spinel is suitable for rings, earrings and pendants. Its hardness and good toughness make it durable for jewellery use, though it should still be protected from impact.

For cleaning at home, use lukewarm water and mild soap. Steam or ultrasonic cleaning requires consideration of fractures, inclusions and treatments. A fracture-filled stone should only be cleaned gently with soapy water or a damp cloth.

Sources Around the World

Familiar spinel sources include Myanmar, Sri Lanka and Tanzania. Colours and qualities vary within each source, and mining origin cannot be identified by colour alone.

Spiritual and Symbolic Meaning — Beliefs and Traditions

Spinel is associated with renewal, vitality and hope. It symbolises reconnecting with inner strength during periods of strain or change, and openness to a more optimistic view of life. It is linked with inspiration and creativity, personal expression and a willingness to let go of beliefs that limit one’s sense of capability. As a personal symbol, it can represent the courage to face challenges, perseverance towards a goal and belief in the possibility of growth and development.

These meanings belong to the realm of belief and symbolism. They can give jewellery personal significance, but they are not proven gemological properties or a promise of healing, protection or a change in health.

Spinel in Personal Jewellery

At TzurGems, we examine the stone and design jewellery around it to highlight its colour and brilliance. Guy’s gemological knowledge and Rafael’s craftsmanship come together in choosing proportions and setting, suited to the stone and the person who will wear it.