Hey Bob, the patent looks pretty technical ! but heres the short version
Abstract
A soft bait lure includes a lure main body (1) formed with an elastic synthetic resin material to have an outer shape resembling a small fish and particles of glass material (2) that are mixed in a lower half portion of the lure main body (1). The lure main body (1) is formed of an elastic material such as vinyl polychloride, polychloroprene rubber, polyisoprene rubber, or natural rubber, etc. The glass material (2) is mixed in a lower half portion of the lure main body (1).
I think we are safe, but thanks for the heads up.
Nova, I've yet to get any myself...do a web search for Tungsten powder and you will find that there are many formulations. Most I found were in the US. If you find a good source PM me and we could split on it....were are you located ?