Geology/History
Cassiterite is a tin oxide mineral (SnO₂) and the principal ore of tin, recognised for its distinctive high lustre and adamantine sparkle. It commonly forms prismatic, pyramidal or stubby crystals, often showing twinning, striations and well-developed terminations. Cassiterite occurs primarily in high-temperature hydrothermal veins and in alluvial placer deposits, where its high density allows it to accumulate as heavy mineral sand.
Its name is derived from the Greek word kassiteros, meaning ‘tin’. Cassiterite has been mined since ancient times, with early civilisations using tin to produce bronze by alloying it with copper. The mineral played a crucial role in the Bronze Age and remains significant in the global tin industry today. Notable historical sources include Cornwall in England, which produced abundant tin for thousands of years and gave rise to a thriving mining culture. Other major sources include Bolivia, China, Indonesia, Russia, Malaysia, Myanmar and the Democratic Republic of the Congo.
Today, Cassiterite is the world’s most important source of tin, which is vital for modern industries. Tin is used primarily as a component in solders for electronics, which form the backbone of circuit boards and electrical connections. It is also used to produce corrosion-resistant alloys, in glass production and for coating other metals. Due to its economic importance, Cassiterite mining is closely monitored under ethical sourcing initiatives, as some deposits in Central Africa have historically funded armed conflict. Certification schemes and responsible sourcing standards now aim to reduce the environmental and social impact of tin extraction, ensuring that Cassiterite supplies come from conflict-free sources.
Cassiterite’s brilliance and durability make fine crystals attractive to mineral collectors and occasionally to gem cutters, though its brittleness limits its use in jewellery. Its resilience to weathering and high specific gravity have long made it an essential placer mineral, forming rich stream and river deposits that sustain artisanal mining communities in many regions today.
Metaphysical Properties
Cassiterite is considered a stone of grounding, focus and manifestation. It is said to support practical thinking, perseverance and the strength needed to see long-term goals through to completion. By aligning with the root chakra, Cassiterite is believed to stabilise energy and foster a sense of self-reliance, particularly during times of change or personal growth.
Metaphysical practitioners value Cassiterite for its reputed ability to clear energetic blockages related to fear, doubt and procrastination. It is thought to encourage personal responsibility, self-discipline and the constructive use of willpower. Some believe Cassiterite helps release the past, allowing one to let go of outworn beliefs and emotional patterns that hinder progress.
Spiritually, Cassiterite is also associated with spiritual grounding during deep meditation or inner work, helping to anchor insights gained into daily life. It is sometimes used to strengthen psychic protection, providing a resilient energetic shield.
Crystal Healing
Cassiterite is said to support detoxification and assist the body’s ability to process dense energies. It is believed to strengthen vitality and stamina, support healthy circulation and aid in balancing mood swings. Practitioners sometimes use it to promote mental clarity and steady decision-making.
Mineralogy
Group: Oxide
Crystal System: Tetragonal
Chemical Composition: SnO₂ (Tin Oxide)
Form/Habit: Prismatic or pyramidal crystals, massive granular or columnar aggregates
Hardness: 6 to 7 (Mohs scale)
Cleavage: Imperfect on {110}
Fracture: Subconchoidal to uneven
Lustre: Adamantine to submetallic
Streak: White to light brown
Specific Gravity: 6.8 to 7.1
Transparency: Transparent to opaque
Refractive Index (R.I.): 1.997 to 2.093
Birefringence: 0.070 to 0.110
Colour: Black, brown, reddish-brown, yellowish-brown, or, rarely, colourless
Pleochroism: None to weak (brownish to yellowish in thin fragments)
Fluorescence: None
Strunz Classification: 4.DB.05 (Oxides with a metal to oxygen ratio of 1:2)
Dana Classification: 4.3.5.1 (Simple Oxides, Tetragonal)