SRI LANKA - One Rupee

A definitive decimal currency One Rupee brass plated Steel coin with a alternat milled + plain edge. There was no Press notice from CBSL on this first issue from the Mint of Finland Ltd., According to CBSL 3.6 Million was first issued 2013 December (quantity confirmed In reply to RTI 0001/17).

They have slight differences to the older Royal Mint coin issued previously between 2005-2011 and again in 2013 when the order with Finland was cancelled and returned to the Royal Mint. I understand it was an issue on quality. See comparison.

DenominationOne Rupee
AlloyBrass plated Steel
Diameter20.0 mm
Thickness1.7 mm
Weight3.65 gms
EdgeMilled + plain edge
MintMint of Finland
SriLanka_r01_obverse SriLanka_r01_reverse
KM #136.4

Obverse : The Armorial Ensign of Sri Lanka

Reverse : The value ONE RUPEE in Sinhala, Tamil and English below and year of issue at the bottom within a circle of the traditional Sinhala Liyavela art with Sri Lanka in Sinhala on top.

SriLanka_r01_2013 finland coin pack
Year Issue
2013 3,600,000

In contrast to the Royal Mint Plastic bags of 1000 coins, the Finland mint coins are issued in very convenient cellophane packs of 100 coins which weighed 370 grams on a digital scale. Printed in Blue on pack is Re. 1 / 100pcs. Ten of these packs were enclosed in a larger pack with Printed in Blue Re. 1 / 1000pcs.

The Finland Mint is located in Helsinki's Katajanokka district was founded by imperial decree on 1860 April 19th.
In 2013 March, it was awarded a contract by CBSL to mint 150 Million Rs1 coins over the next 3 years.

A new master die has been crreated for this coin issue. Many minor differences can be noticed if you overlay and blink the images in a PhotoEditor. The most significant is the first letter of the Tamil ONE(Onru) compared on image on left which is clearly drawn differently from Royal Mint circulation issues since 1963. It is however drawn more similar to that used on commemorative one rupee coins. Pabitra Saha of India, informs me that "The tamil numeral referred to is infact an alphabet (letter) and the present script is the one that is actually used in TamilNadu."

Name of country is still only in Sinhala, as it has been on all circulation coins one rupee and below, which still follow the basic design incorporated in 1972, based on the 1963 design. The Rs2 and Rs5 coin designs first adopted in 1984 and the Rs10 coin design adopted in 2009 have the name of country in all three languages.

In 2014 March, I first found two in circulation, before it had been reported to me by anyone.

The Brass plating appears to be much brighter almost gold-like, but thinner than the Royal Mint coins since on one of the two coins I could see the steel below the plate in the otherwise BU coin.

The grooves on the edge of the coin are less sharp.

I thank Dushanthi (PR-BoC) for getting me packs of these coins on 2014 April 2nd a week before I could have got them from CBSL. The coin was scaned at 600 dpi and the images are displayed at 300 dpi.

Inspection of these 100 coins under 10x magnification showed no significat defects other than typical bag marks.

Weighing each of the 100 coins on a digital pocket scale with a precision of 0.01 grams, I found that the coins weighed between 3.63 amd 3.76 with a mean of 3.67 grams. The distribution had a rms dispersion of 0.0266 (0.72% of mean weight). It had a positive skewness of 0.69 and was leptokuratic with an small positive excess kurtosis of +0.24. i.e. distribution more peaked than normal.

It appears that the coins lower than this range have been removed by some weight control. This would make the measured distribution with the observed positive skewness and kurtosis. This is unlike the Slovak and Royal Dutch Mint which appears to have clippbed both lower and higher of a weight range, and British Royal Mint which did not remove any coins on weight