Dancing Steel

- The proc chance is 2.3ppm (was 2ppm before patch 5.2).

- It can dual proc if you have it on MH+OH (since 11/29/2012 hotfix).

- It has no Internal Cooldown (ICD) so the buff can refresh.

Please do not downvote helpful information.

With the new ability of enchanters to 'upgrade' MoP enchanting mats to higher tiers, it would take exactly 1356 spirit dust to create one dancing steel enchant from scratch. (1 sha crystal = 3 ethereal shards = 9 greater mysterious essence = 27 lesser mysterious essence = 135 spirit dust).

EDIT: Since beta this has been changed, so as Seiryuu correctly points out, 1 Sha Crystal = 5 Ethereal Shards = 25 Mysterious Essences = 125 Spirit Dust hence 1262 dust is now required for this enchant.

The devs told us exactly how MoP weapon enchants work at the link below.

http://us.battle.net/wow/en/forum/topic/6397900436?page=8#154

I'm pasting it here in case they retire the beta forums after release.

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• River's Song: 4 RPPM on melee attacks that land, or are dodged, or parried.
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• Dancing Steel: 2.3 RPPM on melee attacks that land.
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• Colossus: 6 RPPM on melee attacks that land, or are dodged, or parried, with a 3-second cooldown.
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• Elemental Force: 10 RPPM on damage or spell damage/healing
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• Jade Spirit: 2 RPPM on spell damage or healing, 50-second cooldown.
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• Windsong: 2 RPPM on damage, or spell damage/healing.
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Edit: As of 10/15/12, Windsong and Elemental Force now proc on all damage and healing, including melee, ranged, direct and DoT.

They now trigger on the new "Real Procs Per Minute" (RPPM) system, which is weapon speed and instant attack independent and fully detailed in this blue post.

http://us.battle.net/wow/en/forum/topic/6893549789

Edit 2: As of patch 5.1 Dancing Steel, Jade Spirit, River's Song, and Colossus are on the RPPM system also.

Edit 3: As of patch 5.2, Dancing Steel now has a 15% greater chance to activate.

Source: http://us.battle.net/wow/en/blog/8896363/52_The_Thunder_King_Patch_Notes-3_5_2013