It is a piece of lava, yes.
To generalise, minerals filling vesicles in lava are likely to be agate/zeolite/calcite/quartz.
It would be necessary to look at the minerals in thin section under a microscope to get a reliable ID.
Maybe the photo does not do the specimen justice; is it really metallic in lustre?
Assuming so, pyrite would be much more likely than gold, and the surface texture is more pyrite-like than gold-like. Try testing the hardness: pyrite is 6-6.5 (you'd have difficulty scratching it with a needle); gold is about 3 (easily scratchable with a needle).
I just started a Geology BA at university, I hold Ba degree, but passion is passion, I love rocks, fossils, nature..
Don`t have microscope yet...
But I`ve checked hardness and it very easy to scratch.
Thanks for the further photos.
The striation is obvious, and what might be a plane of cleavage, but those are not enough. In combination with the softness and colour, however, I think it might be one of the softer zeolites, such as stilbite or heulandite (I also wonder about siderite or ankerite).
This mineral ID key may be of interest
That's part of a brilliant key which starts here
But you should read the introductory page first
The authors have done a great job; hats off to them from me.
If you find out what it is (eg. once you've got your hands on a microscope and have some experience under your bel)t, please let us know!
Thank you for giving us some background on yourself. It does make a difference.
In this case, it also allows me to wish you well in your studies, and in your journeys and friendships along the way.