Dating tibetan coins
Subsequently silver coins of a reduced weight standard, mohars, were struck by the kings of the three Malla kingdoms which shared the Kathmandu valley.
In the 18th century special debased mohars were struck by Nepal for Tibet. These followed the Nepali fabric and type with minor differences to assert their local origins.
The Kong-par tangkas were struck from 1791 to 1891.
The design of these tangkas remained nearly invariable for several decades.
The first tangkas were struck in Nepal from about 1640.
From this period onwards many Nepali tangkas were exported to Tibet.
You can convert the Tibetan date to our western [the Julian calendar] date here This coin is 24 mm, which is slightly smaller than a U. quarter, and is made of copper; it comes in a gift box with a lifetime warranty.
The last Sino-Tibetan issues of the 19th century are dated to the 16th year of the Dao Guang era (AD 1836).
The first indigenously minted Tibetan tangkas which were produced on a large scale are known as the Kong-par tangkas.
Coins are all originals and may bear slight variations due to wear.
century coins to the present use Vikram Samvat era (VS) dates.
The year is about on your first photo, and is worn, but appears to read 58 as well as I can make out (perhaps you can read it better with the coin in hand).