These are nice coins made out of copper-nickel issued by Reza Shah Pahlavi between 1966 and 1978, which correspond to Islamic solar dates SH1345 and SH1357. Some coins use other dating systems. You can see the denomination (10 or 20) written under the lion, and the Islamic date written under Pahlavi in eastern Arabic numerals.
The 20 rial coins are slightly larger than the 10 rials:
10 RIALS: about 23 mm diameter
20 RIALS: about 29 mm diameter
With few exceptions, catalog values are the same for 10 and 20 rial coins:
worn: less than $1 US dollar approximate catalog value
average circulated: $1
well preserved: $3
fully uncirculated: $8
Be sure to read our Important Terminology page which gives information about converting catalog values to actual buy and sell values.
There are a few coins which are worth slightly more than the values above, as follows. Values are for coins in well preserved condition.
10 RIALS with FAO under the lion: $6 in well preserved condition
10 RIALS dated SH1357, not 2537: $20
20 RIALS dated SH1357, not 2537: $15
20 RIALS dated 2535 or 2536: $12
20 RIALS with FAO under the lion: $12