What you probably have is an alloy belonging to the group
"Cerro-Bend". Related to Kirksite, Woods, and Fields metal alloys.
All are called “fusible metals”.
It has a very low temperature melting point - 158 degrees… Mostly
bismuth. You do NOT want to alloy it with any precious metal, nor
contaminate your precious metal filings or any scrap to be
We use it to mount certain firearms parts while inlaying or
engraving. It is also used to check chamber measurements in
rifles… Machinists use it for various jigs, and to get precise
inside bore measurements. Hobbyists use it to cast model railroad
parts & such.