1971 - Lanka

Five Cents - TRIAL

A set of TRIAL patterns were struck with date 1971 to select a cheaper alloy for the Five cents and Ten cents coins in which the Nickel-Brass metal had become almost half the face-value. Patterns were struck for both Five cents and Ten cents denominations in Nickel-Brass clad steel, Chromized steel, and Aluminum with word TRIAL in raised letters on Obverse at 2 O'clock. Rare 1975 Aluminum off-metal-strikes (OMS) also exist for both Five cents and Ten cents. Aluminum was adopted and made legal for the Five and Ten cents coins from the 1978 issue. Aluminum had been used for the one and two cents coins since 1963.

SPECIFICATIONS
DenominationFive cents
AlloyNickel-Brass clad Steel
Diameter21.46/18.24 mm
Thickness1.55 mm
Weight3.18 gms
ShapeSquare with round corners
EdgePlain Steel
Die-Axis
1971_Lanka_05c_clad_trial_obverse 1971_Lanka_05c_clad_trial_reverse
KM unlisted
DenominationFive cents
AlloyChromized Steel
Diameter21.46/18.24 mm
Thickness1.41 mm
Weight2.80 gms
ShapeSquare with round corners
EdgePlain
Die-Axis
1971_Lanka_05c_steel_trial_obverse 1971_Lanka_05c_steel_trial_reverse
KM Unlisted
DenominationFive cents
AlloyAluminum
Diameter21.46/18.24 mm
Thickness1.55 mm
Weight0.98 gms
ShapeSquare with round corners
EdgePlain
Die-Axis
1971_Lanka_05c_al_trial_obverse 1971_Lanka_05c_al_trial_reverse
KM unlisted

Obverse : The Armorial Ensign of Ceylon, with word TRIAL to the right and upper side (2 O'clock) along the periphery.

Reverse : The large numeral 5 with the value FIVE CENTS in Sinhala, Tamil and English below and year of issue at the bottom within a circle of the traditional Sinhala Liyavela art with Lanka in Sinhala on top.

Considering the weight, thickness and edge of the coins it appears that the Steel core of the Nickel-Brass Clad pattern is similer to the Chromized Steel pattern.

Qualitative x-ray floresence spectra show the clear presence of Chromium with the Iron in the Chromized Steel TRIAL. NO trace of Chromium was detected on exposed Steel core along the edge of the Nickel-Brass Clad TRIAL. No Iron was detected on surface of same coin indicating a thick clad of Nickel-Brass.

I have seen 2+5/6 sets of these TRIAL coins. I am seeking information about other sets of these Pattern I am not sure how many were produced or known to exist. Retired officer T. M. U. Sallay of the Central Bank of Ceylon, confirmed them to be official Patterns.

There is also a 1968 Five Cents with word TRIAL in raised letters on both Reverse (10 O'clock) and on Obverse (9 O'clock). It is non-magnetic and of the same weight and metal as the standard issue of that year. It was struck most probably in Birmingham Mint when they got the subcontract from the British Royal Mint (BRM) which first struck it few years previously in 1963.

The TRIAL coins were scanned at 600dpi and the images are displayed at 300dpi.