Please enable JavaScript.
Coggle requires JavaScript to display documents.
CRYSTAL, K9 Glass v K9 Crystal - Coggle Diagram
CRYSTAL
Glass
Least Expensive
Least Clear
Made of silica sand
Pure Silica Sand = Crystal Clear Glass (low/no iron)
TWO versions
(both very hard material)
Crystal Clear Glass
(slightly softer)
(double $ of Jade)
"Float" glass
Closely resembles Crystal
might have a slight blue tint
Jade Glass
higher % of iron
Gives it it's green/blue tint color
(seen on the edges)
extremely hard material
Difference between Glass & Crystal
is determined by "REFRACTIVE INDEX" scale
Glass has low refractive index
Crystal has high refractive index
High Index = 1.5 = Classified as Crystal
Low Index = UNDER 1.5 = Classified as Glass
HARD CRYSTAL
OPTICAL CRYSTAL
Short for "ophthalmic" crystal
(means Lenses)
How it's made:
-heated at high temps
-Allow to cool very slowly
-This eliminates any imperfections
and bubbles
Result:
-Very hard material
-much clearer than glass or Lead crystal
For this reason, Optic is the MOST EXPENSIVE
Cheaper Option
K9
Optical Borosilicate Crown Glass Crystal
low-dispersal properties
high refractive index
High Clarity
K9 is equivalent to BK7 ???
Lower production cost
Lighter & Cheaper compared to other glass crystals
Today, almost all optic crystals are made from k9
(however, quality for this crystal varies widely)
Cheapest versions of k9 have NO UV(ultraviolet) light resistance, will turn yellow if exposed to any UV light
SOFT CRYSTAL
LEAD CRYSTAL
Has added element of LEAD OXIDE
(This softens glass and gives it shine)
Lead oxide of up to 35%
-allows it to be formed, blown, molded easier
Easy to grind & Polish
"Full lead crystal" must have AT LEAST 24%
There is Italian lead crystals
There is German Crystal?
K9 Glass v K9 Crystal
More than 24% is k9 crystal
Borosilicate Optical Crystal
10% lead content
mass produced from china
low inclusions (no bubbles or stuff in it)
-why it's perfect for optics
Less than 24% is k9 glass
Source