Crystal candies prevent the player from using that covered tile to switch, and all moveable elements pass through Crystal Candies. However, one can switch using a candy adjacent to the covered candy, and then switch it to the covered tile.
For the list of levels with this blocker, see here.
Crystal candies encase other elements, similar to marmalade and liquorice locks. However, they can be cleared by making matches underneath them (by moving the candy outside the crystal candy into it to create a match).
Candies and movable blockers can pass through them like jelly. Elements such as liquorice locks and conveyor belts can be underneath them.
They can also be destroyed by special candies but they can't be destroyed by making regular matches next to them.
If an immovable blocker is underneath crystal candies it can only be destroyed with special candies.
A one-layered crystal candy that encases an immovable blocker behaves exactly the same way as a liquorice lock.
If an ingredient goes to an ingredient exit that has jelly, the ingredient will be collected normal and the jelly will lose one layer like it was hit by a special candy. This is, however, not true if the jelly is protected by crystal candy - in such case, neither the jelly nor the crystal candy will lose one layer.
If there is a double jelly underneath a 5-layered waffle in a 3-layered sugar coat which is in a 3-layered crystal candy in a spot where it can't be moved, it will take thirteen hits to get rid of that one square of its jelly unless a jelly fish is used.
Crystal candies do not block the flow of rainbow rapids in rainbow rapids levels.
Level 4596 - First level with one-layered crystal candy, two-layered crystal candy, crystal candy order, empty crystal candy and first candy order level with crystal candy.
Level 4597 - First level with three-layered crystal candy, first level with toffee swirls in crystal candy and first ingredients level with crystal candy.
Level 4598 - First jelly level with crystal candy and first level with multilayered frosting in crystal candy.
Level 4600 - First mixed level with crystal candy and first level with liquorice locks in crystal candy. Also, the liquorice locks in crystal candy contain special candies.
Level 4603 - First moves level with crystal candy, first level with candy bombs in crystal candy and first level with conveyor belts that travel through crystal candy.
Level 4608 - First level with liquorice shell, non-spawning colours and liquorice swirls in crystal candy.
Level 4615 - First level with sugar keys and sugar chests in crystal candy. Also, the sugar chests in crystal candy contain liquorice swirls, striped candies and dark chocolate.
Level 4629 - First level with locked ingredients in crystal candy.
Level 4636 - First jelly-order mixed level with crystal candy order.
Level 4645 - First level with two-layered frosting in crystal candy.
Level 4657 - First level with jelly fish in crystal candy.
Level 4682 - First level with lucky candies in crystal candy.
Level 4730 - First level with coconut wheels in crystal candy.
Level 4748 - First level with colour bombs in crystal candy.
Level 4757 - First level with locked UFOs in crystal candy.
Level 4761 - First level with (Not locked) UFOs in crystal candy.
Level 4781 - First level with candy frogs in crystal candy.
Level 4783 - First level with cake bombs in crystal candy.
Level 4812 - Formerly the first level with empty sugar chests in crystal candy.
Level 4828 - First level where regular magic mixers can spawn crystal candies.
Level 4839 - First level with mystery candies in crystal candy.
Level 4857 - First level with marmalade in crystal candy. Also, the marmalade contains liquorice swirls.
Level 5193 - First level with locked candy frog in crystal candy.
Level 5284 - Formerly first level with chameleon candies in crystal candy, before their removal.
Level 5551 - First level where crystal candies are required on a board where they don't appear or spawn from magic mixers.
Level 6014 - First level with sugar coats in crystal candy.
Level 6113 - First ingredients-order mixed level with crystal candy order.
Level 6571 - First level with bubblegum pops in crystal candy.
Level 7128 - First appearance of one- and two-layered crystal candies in rainbow rapids levels.
Level 7156 - First appearance of three-layered crystal candies in rainbow rapids levels.
Level 8154 - First level with order lock in crystal candy. First level with yellow candy order lock in crystal candy.
Level 8272 - First level with sour skull in crystal candy.
Level 8317 - First level with dark chocolate order lock in crystal candy.
Level 8364 - First level with toffee swirl order lock in crystal candy.
Level 8365 - First level where crystal candy order is required to unlock order locks.
Level 8499 - First level with candy frog order lock in crystal candy.
Level 8849 - First level with bonbon blitz in crystal candy.
Level 9009 - First level with a different colour scheme where crystal candies appear.
Level 9084 - First 6-coloured level with crystal candies.
Level 9174 - First level with dark chocolate fountain in crystal candy.
Level 9844 - Officially the first with jelly jars in crystal candy.
Level 10006 - First five-digit level with crystal candy.
As of HTML5 version 1.172, the crystal candy has a glitch. Sugar chests cannot be unlocked when they are covered by crystal candies.
This is one of the HTML5 exclusive blockers that resembles another blocker and is multilayered. This one seems to resemble Marmalade and Liquorice Locks, except they can have up to three layers and they can be cleared by swapping the candy inside with another candy to make a match inside them.
This blocker was released approximately one year (52 weeks exactly) after Candy Cane Fences, the first blocker exclusive to HTML5 version.
This is the first element to be required for candy orders in the level it debuts in.
Crystal candies make up the numbers 122, 123 and 124 in the tile map code (one-layered crystal candy, two-layered crystal candy and three-layered crystal candy, respectively).
This is the first blocker that can properly encase other encasing blockers. Candy cane fences and candy cane curls can surround other encasing blockers but it's possible to destroy the blocker they surround without breaking them completely.
That is because the Crystal Candy is "above" that of an encasing blocker, which in turn is "above" a Sugar Coat, which lies above candies and most immovable blockers.
This can lead to elements other than the candy frog being encased in two blockers at once, such as special candies in level 4600, ingredients in level 4629 and liquorice swirls in level 4857.