Well in code we're using C#'s decimal type (128 bit. 96 bits are used for an integer and the rest used for the sign and scaling factor) [0]. It's essentially just floating point applied to a base 10 integer rather than a binary one.

In the SQL server database the column types are usually decimal(18,5) or decimal(25,12) [1]

[0] - https://docs.microsoft.com/en-us/dotnet/api/system.decimal?v...

[1] - https://docs.microsoft.com/en-us/sql/t-sql/data-types/decima...

thanks! Someone else also pointed at lack of 128-bit long support. It looks as if long128 might help here.