Jardines Galleries · Interactive coins · South African inventions
The Crown & Tickey Inventions Series.
A pair of sterling-silver coins launched in 2016 in which the smaller 2½c tickey physically slots into a recess on the larger R2 crown to recreate the invention being commemorated. The tickey becomes the heart being transplanted, the lens of the CT scan, the Ranger spacecraft on the lunar surface, the retinal cryoprobe in a gloved hand. Each year features a different South African first: dolosse (1963), heart transplant (1967), CT scanning (1956), Pratley Putty on the moon (1969), retinal cryoprobe (1965). Five sets to date — typically 700 sets per year at the boxed-pair tier.
Interactive by design
Tickey slots into crown · The design completes(circular recess)
(insert)
recreated
Each crown carries an empty circular recess within its reverse design. When the matching tickey is placed into the recess, the tickey becomes the missing element of the invention being commemorated — a heart in the chest, a lens on the head, a spacecraft on the moon. The two-coin set isn't just a pair; it's a completed design.
South African firsts
2016 launch · One invention per year · Sterling silverThe series celebrates globally significant inventions originated by South Africans — a coastal-engineering breakthrough, a surgical first, a Nobel-prize-winning imaging technique, a polymer that reached the moon, an ophthalmic procedure that restored a president's sight. Five inventions across five years, all rendered in sterling silver (Ag 925) at proof finish.
The obverse — common across both coins of the pair — carries the Coat of Arms of South Africa and the words "South Africa" in all eleven official languages, arranged in a pentagonal pattern. The series is the SA Mint's most explicit constitutional gesture in a circulating commemorative format.
Series overview
Sterling silver · Designed by ALS & PB · Annual issues since 2016Each year features a matched pair: an R2 crown (38.725 mm, 33.626 g) and a 2½c tickey (16.30 mm, 1.414 g), both struck in sterling silver (Ag 925, Cu 75) — exactly one ounce of pure silver in the crown (1.000 oz ASW). The tickey is engineered to fit the recess on the crown precisely, completing the reverse design.
The obverse of both coins, designed by Arthur L. Sutherland (initials ALS), features the South African coat of arms and the words "South Africa" in all eleven official languages arranged in a pentagonal pattern. The reverse of each crown carries the metal-content inscription "1oz Ag925 Cu75" and the initials of the die-sinker, Paul Botes (PB). Reverse design credits vary year-to-year — CVB Jeppe and RC Stone appear on the 2017 and 2019 reverses; Paul Botes is the constant engraver.
"The two coins are aimed to celebrate a different South African invention which comes with an extraordinary history and heritage. Under the new theme of South African inventions, the beautifully crafted R2 Crown and 2½c Tickey will offer coin collectors a lifetime of appreciation."
— Tumi Tsehlo · Managing Director, South African Mint · 2016 launchThe five inventions
Year by year · Crown reverse · Tickey reverse · MintageEach issue carries the same structural template — R2 crown with circular recess, 2½c tickey that fits the recess, sterling silver throughout. The thematic content and the way the tickey completes the crown change every year with the invention being celebrated.
The Dolos · launch issue
The series' inaugural year commemorates the dolos — invented in East London in 1963 by harbour engineer Eric Mowbray Merrifield and his draughtsman Aubrey Kruger to protect harbour walls from wave damage. The dolos's unique interlocking shape creates a porous wall that dissipates wave energy rather than absorbing it. Roughly 10,000 dolosse are required to protect a kilometre of coastline; individual dolosse weigh up to 30 tons. The design has been adopted globally and is one of the more practically consequential South African engineering exports.
People on a harbour wall
Figures stand on a harbour wall protected by a field of dolosse. The circular recess sits where the central dolos belongs. Die-sinker: Paul Botes.
A single dolos
One dolos in three-quarter view, with the denomination 2½c. When inserted into the crown, the harbour wall acquires its completing piece.
First human heart transplant · 50th anniversary
Commemorates the 50th anniversary of the first successful human-to-human heart transplant — performed by a team led by Dr. Christiaan Neethling Barnard at Groote Schuur Hospital, Cape Town, on 3 December 1967. The procedure made Barnard internationally famous overnight and remains the South African medical event of the twentieth century.
The chest cavity
A human torso indicates the position of the heart, with "First heart transplant" and the year 1967. The circular recess sits exactly where the heart belongs — the empty cavity.
The heart
A human heart, the denomination, and "CNB" (Christiaan Neethling Barnard). Inserted into the crown, the heart is transplanted. The most literal of the series' design metaphors.
Computed Tomography · the CT scanner
Honours the development of computed tomography (CT) — invented by South African–American physicist Allan McLeod Cormack, whose 1956 work on cross-sectional X-ray imaging earned him a shared 1979 Nobel Prize in Physiology or Medicine. CT scanning uses computer-processed X-ray measurements from many angles to construct cross-sectional images of the body — the foundation of modern medical imaging.
The scanned head
A human head with overlaid computer printouts indicates the area being scanned. Above right: 1956 — the year of Cormack's foundational work. The circular recess sits at the imaging plane.
The scan itself
When inserted onto the crown, the tickey gives the impression of a CT scan slice — the cross-section that Cormack's mathematics made readable. Reverse designer: Paul Botes.
Pratley Putty · the South African product on the moon
Celebrates Pratley Putty — invented by George Montague (Monty) Pratley in the 1960s as an industrial insulator and adhesive. It is the only South African product to have gone to the moon: used on the NASA Ranger spacecraft in 1964 and 1965 to help lay the groundwork for the Apollo 11 moon landing of 1969. The 2019 issue also commemorates the 50th anniversary of the first lunar landing (1969 – 2019).
Earth from above the moon
Earth as seen from above the lunar surface, with Africa and South Africa prominently displayed. The Apollo 11 module and lunar lander appear, with the dates 1964, 1965 (Ranger missions), 1969 (first moon landing), and 2019.
The Ranger spacecraft
A portion of Africa with South Africa in the foreground, the moon's surface, the Ranger spacecraft, and the initials "GMP" (George Montague Pratley). Inserted onto the crown, the Ranger reaches the lunar surface.
The retinal cryoprobe
Honours the retinal cryoprobe — developed by South African ophthalmologist Dr. Selig Percy Amoils at Baragwanath Hospital, Soweto, in 1965. The cryoprobe is a pen-like cryosurgical instrument used to treat cataracts, the world's leading cause of blindness. Its most famous patient: President Nelson Mandela, whose cataract Dr. Amoils removed days after Mandela's 1994 inauguration — South Africa's first democratically elected president, treated with a South African–invented procedure.
The anatomy of an eye
Cross-section of the human eye, with the years 1965 and 2020 and the words "RETINAL CRYOPROBE". The circular recess sits at the lens — the site of the cryoprobe procedure.
The gloved hand
A gloved hand holding the retinal cryoprobe, the letters "SPA" (Selig Percy Amoils), and the denomination. Inserted onto the crown, the cryoprobe reaches the eye — the procedure recreated in metal.
Technical specifications
Identical across all five issues · Sterling silver · Proof finishThe crown-and-tickey pairing is structurally constant across the series. Both coins struck in sterling silver (Ag 925, Cu 75) at proof finish, with the crown carrying exactly one ounce of pure silver (1.000 oz ASW). The tickey is sized precisely to fit the crown's recess.
| Denomination | Mass | Diameter | Metal | Silver weight |
|---|---|---|---|---|
| R2 Crown | 33.626 g | 38.725 mm | Ag 925 · Cu 75 | 1.000 oz ASW |
| 2½c Tickey | 1.414 g | 16.30 mm | Ag 925 · Cu 75 | ~0.042 oz ASW |
Collecting the series
Set scarcity · Premium combos · Krugerrand pairingsFive issues to date make the series genuinely completable at the boxed-pair tier — but the premium combinations (silver model bonuses, Krugerrand launch sets) materially raise the bar.
Complete sets in original packaging with certificates are the most collectible format. Mintages run 700 – 1,000 sets per year at the standard tier, with premium combinations tracking lower (e.g., 374 Krugerrand & Crown sets in 2019, 500 Krugerrand combos in 2020). The series has the structural advantage of being annually predictable — a known release cadence from a known issuer with consistent specifications — which makes set-completion a tractable target rather than a chase.
Years with additional silver models in the box command meaningfully higher prices: the 2016 dolos miniature, the 2019 sterling-silver Ranger 9 in walnut casing, the 2020 silver eye sculpture. The Krugerrand & Crown launch sets introduced in 2019 and 2020 pair the year's commemorative crown with a privy-marked silver Krugerrand at very low mintages (500 sets) and command the series' highest prices in the secondary market.
(Worth comparing to the UNESCO Man and the Biosphere series, which shares the SA Mint's structurally-integrated commemorative approach but stopped at two of eight planned releases. The Crown & Tickey series — with five-year continuity through 2020 — is by contrast the SA Mint's most consistent recent commemorative programme.)
- South African Mint — "Innovations" newsletter, February 2017.
- South African Mint — Customer newsletter, April 2017.
- South African Mint — "2017 Collectable Coins Brochure."
- South African Mint — "2020 Range — Crown and Tickey: Retinal Cryoprobe."
- Online Coin Club — "Silver Crown 2018 Computed Tomography" entry.
- Online Coin Club — "Silver Crown 2019 Polymer Putty" entry.
- APMEX — "2019 South Africa 2-Pc Silver Inventions: Polymer Putty."
- CoinWeek — "South African Mint Continues Inventions Series With 2020 Retinal Cryoprobe Coins."
- The Citizen (Fourways Review) — "Something new for coin collectors," June 2016.
- Cross-references: UNESCO Man and the Biosphere Series (parallel SA Mint commemorative · structurally-integrated multi-coin sets), Natura Series (the SA Mint's flagship pure-gold commemorative programme), South African Mint Today, Commemoratives Hub.