The singular noun form is glass.
There are two accepted forms for possessive singular nouns that end with an s:
Add an apostrophe (') after the existing s at the end of the word:
Add an apostrophe s ('s) after the existing s at the end of the word:
Examples:
The glass' monogram is that of my grandfather.
The glass's monogram is that of my grandfather.
The possessive form for the plural noun glasses is glasses'.Example: Her glasses' frame broke when she dropped them.
Quantum is singular, not singular possessive. The singular possessive form is quantum's.
The singular possessive form for the noun clock is clock's.
The possessive form for the singular noun speed is speed's.Example: This device will measure your speed's velocity.
Glass's
The possessive form for the singular noun glass is glass's (just as you have it in your question).The plural form is glasses. The plural possessive form is glasses'.Example: I like these glasses' pattern the best.
The noun glass has a number of uses, all of them are uncountable nouns, except for a drinking glass. The plural possessive is glasses'; the set of glasses' color.The singular possessive for a pair of glassesused for eyesight is glasses', the glasses' frame. The plural possessive is the glasses' frames. The plural possessive is the same because it is a shortened form for the pairs of glasses' frames.The singular possessive for a pane of glass, used for windows is the glass's size. The plural possessive is the glass's sizes. The plural possessive is the same because it is a shortened form for the panes of glass's size.
The singular possessive form of "test" is "test's".
The singular possessive pronouns are mine, yours, his, hers, and its. The singular possessive adjectives are my, your, his, her, and its.
The singular possessive is ant's.The plural possessive is ants'.
Museum is singular. Museum's is singular possessive. Museums is plural. Museums' is plural possessive.
The possessive form for the plural noun glasses is glasses'.Example: Her glasses' frame broke when she dropped them.
The singular possessive of dish is dish's
Taco's is the singular possessive.
The singular possessive form is classmate's.
The singular possessive is biker's; the plural possessive is bikers'.
The singular possessive is fish's.