Whitman Expo
New coins from Australia and New Zealand.
Thank you to our sponsors!
Go check them out!
Obverse Description
Above a spray of oak and laurel, the national coat of arms depicting the eagle in profile to the left, with feathers resembling plates of armor. Above, the legend ESTADOS UNIDOS MEXICANOS.
Reverse Description
At center of a dodecagonal (12-sided) field, a large 20¢ with the date above and the mintmark M below. From upper left to lower right, a partial border of repeated Reed (Acatl) glyphs, representing the 13th-day glyph on the Aztec Calendar Stone.
Catalog Information
GSID:
294997
Obverse Lettering:
ESTADOS UNIDOS MEXICANOS
Reverse Lettering:
CULTURA OLMECA, Mo, 1983, 20¢
Weight (gr):
3.04 gr
Coin Rulers Name:
United Mexican States/Mexican Republic
Strike Type:
Business
Diameter:
20
Coin Shape:
Round
Edge:
Reeded
Variety:
Type 9, Olmec
Variety 2:
KM-491
Coin Date:
1983-Mo
Denomination:
20c
Designation:
MS
Mint Location:
Mexico City
Mint Mark:
Mo
Mintage:
200,000,000
Coinage Type:
Coinage Reform of 1905
Coinage Years:
1983-1984
Composition:
Copper
Krause #:
KM-491
Send Catalog Feedback
To: editor@greysheet.com
Subject: I would like to contribute catalog info to CDN for 1983-Mo 20c Type 9, Olmec, KM-491 MS (KM-491)
Body: Referring page: http://livetest.greysheet.com/prices/item/1983-mo-20-centavos-type-9-olmec-km-491-mexico-world-coins-km-491-294997/gsid/294997 GSID: 294997 Title: 1983-Mo 20c Type 9, Olmec, KM-491 MS (KM-491)
Subscribe to View
Log In
View more data, info, and visualizations. Get access to retail and wholesale pricing as well as auction data.
Coin Value History
1983-Mo 20c Type 9, Olmec, KM-491 MS (KM-491)
Value By Grade
1983-Mo 20c Type 9, Olmec, KM-491 MS (KM-491)
CPG (retail) values
Currency
Grade Range
Sort by
Pricing
1905-M 20c Type 1, KM-435 MS
Worth: $8 – $150
1906-M 20c Reform, Type A1, KM-435 MS
Worth: $6 – $135
1907-M 20c Reform, Type A1, Straight 7, KM-435 MS
Worth: $8 – $400
1907-M 20c Reform, Type A1, Curved 7, KM-435 MS
Worth: $8 – $200
1908-M 20c Reform, Type A1, KM-435 MS
Worth: $65 – $10,000
1910-M 20c Reform, Type A1, KM-435 MS
Worth: $9 – $150
1910-M 20c Reform, Type A1, Second 1/Inverted 1, KM-435 MS
Worth: $8 – $260
1911-M 20c Reform, Type A1, KM-435 MS
Worth: $10 – $180
1912-M 20c Reform, Type A1, KM-435 MS
Worth: $28 – $525
1913-M 20c Reform, Type A1, KM-435 MS
Worth: $9 – $90
1914-M 20c Reform, Type A1, Narrow Date, KM-435 MS
Worth: $9 – $185
1914-M 20c Reform, Type A1, Wide Date, KM-435 MS
Worth: $9 – $125
1919-M 20c Type 2, Little, KM-436 MS
Worth: $21 – $325
1920-Mo 20c Type 3, Monogram, KM-437 MS BN
Worth: $45 – $500
1935-Mo 20c Type 3, Monogram, KM-437 MS BN
Worth: $10 – $180
Greysheet News
Weekly World Mint Coinage: September 17, 2026
9/17/2026
Five U.S. Coins Bring 7 Figures in $67 Million+ Heritage ANA Auctions
Scandinavian gold rarities also command exceptional results.
9/11/2026
Events
Heritage Auctions: US Coins Tuesday & Wednesday Select Auction
Location: Heritage Auctions
Wednesday, July 1, 2026
Heritage Auctions: World & Ancient Coins Wednesday & Thursday Select Auction
Location: Heritage Auctions
Thursday, July 2, 2026
