Information Needed On Hyroz Glass Thought To Be Czechoslovakian

I purchased this extremely heavy 7 1/2" flecked glass bowl online. Seller said it was signed but the identification is a glass glob medallion that says Hyroz. In my search I found a post of 3 years ago someone trying to identify his Hyroz vase. There is also a Hyroz vase on Worthpoint that sold for $129. I don't think this is a very common item but would love further information. For its size it is extreme heavy. Thank you in advance for any information.