HI ,
Sorry Otis but your paper test is of no value,to fake ware the object is placed on an abrasive surface,concrete or rough sand paper to name just 2, the object is then pressed down and moved randomly around which creates ware looking marks on the 'high' points,the points your paper test detects ware,this takes but moments to do so is no trouble to anyone,you don't have to pay any attention to the under surface to achieve this the high points will make contact and produce the results , I have seen this done on pieces like this in Spain.
You also say that this piece has extensive ware ,in my experience pieces from the 17th century and earlier and of course later which like your piece are very light and of non lead glass the signs of ware can be very minimal because the object does not have the weight that would be needed to create extensive ware from normal daily use even over 100rds of years,in comparing ware on pieces from the 17th and 18th century which are non lead to pieces of lead glass from the 18th c the lead glass will show a far greater level of ware due to its own weight and the effects of daily use.lead glass of course being softer than non lead glass,in comparing lead glass and non lead glass from the 18th century non lead always shows less ware than lead ,its harder.
so extensive ware on a very light piece of glass is always suspicious.
You previously commented that the' quality of a final end piece piece was not important' , I have to disagree with this, when considering if an object may be from the 18th c or earlier quality at this time was paramount, the world was after the best quality available everyone was trying to beat the Venetians who until the last half of the 17thc had the monopoly of quality glass world wide which is why so much effort was put into the research of new recipes which in the end produced lead crystal.
Your piece display none of the attributes I would associate with early piece of glass , the form , the colour and the bubbles along with the fire polished pontil all suggest a much later production , that is not to say that it does not have some age , others here will be better placed to give an opinion as to the possibilities of it being along the lines of Walsh or some other from that time period who produced bubbly pieces like this ,my interest in glass I am afraid ceases around 1800.
In conclusion I would say that this item is not from the 16th 17th or 18th c. My visual awareness(re the posted pics)is I believe pretty well honed from 25 yrs of collecting, buying, selling and personally handling thousands of period pieces in collections and museums both at home and abroad,and as this is a forum that can only judge from photos I can say no more unless you would like to send it to me to personally inspect though I am certain this would be a waste of both time and money .
cheers ,
Peter.