ring markings mens signet ring

by kelly jenkins
(leighton buzzard, bedfordshire)

Hi there,

We have a ring in the family, a gold signet ring with what i can only describe as a lightening strike surrounded by a circle on the top. The only markings inside the ring are in triangles, one an 18k the other what i thought was 75 degrees ( small circle ) but what must be 750.

There are no other hallmarks. Just wondered if you had any idea of the era it came from and value? Any idea on the markings on top of the ring and also, is it genuine gold?

THank-you, look forward to your reply.