This creature is best described as a Gem type Draconic Species

All known Black Opal Pseudodragons have been chaotic Good...but not enough have been observed to make an all-inclusive claim to that effect

Tiny: Pseudodragons grow to about the size of a housecat.

Black Opal pseudodragons do not have opposable thumbs. They can not hold or use weapons meant for the hand, however they can wear rings as bracelets, bracelets as belts and necklaces whose chains can be looped multiple times.  They can also wear magic items which resize themselves instantly or upon attunement

The Black Opal Pseudodragon can scamper 25' on the ground, climb at 15', swim at 15', and can fly at 50' per round, also able to hover in place..

Darkvision to 60'

Blindsight 30'

Tremor Sense to 30' (the difference to blindsight is that tremorsense can detect through walls. Tremorsense also only functions while the creature is in contact with a physical surface.  It does not function if the creature is in flight)

Languages: Understands, reads, and writes Common, Draconic, but lacks vocal cords.  Can speak either language psychically but to only one person at a time, who may respond as long as the connection is maintained.  In combat, Pseudodragon must make concentration checks when damaged to maintain psychic connection

Your natural swiftness in the air causes your dexterity Score increases by 2. 

Your stunning beauty (when seen) causes your charisma score increases by 2.

Your tiny size causes your strength score decreases by 1.

Black Opal Stealth - The black opal dragon can blend with shadows to become almost invisible, and both flight and movement are silent.  She has expertise and rolls with advantage on stealth while in dim light.

In  direct sunlight or daylight (Does not include interior lights in buildings.) she drops from expert to proficient in stealth and rolls at a disadvantage.

They also have proficiency in perception and are expertise in hunting and survival.

Ability to hide in plain sight - Black Opal Pseudodragons are so adept at working with light and darkness that they have advantage to hide in any shadow including those cast by the body of an enemy. The amount of sunlight or daylight provided by forest cover and such are left to DM discretion on whether their hide ability can be applied.

Their fluid scales are much like the glass created by their breath weapon, and they will harden and become stronger over time. Their scales provide AC improvement - 13 + Dex Modifier when unarmored. as the dragon ages this improves and the base Ac Increases 1 every 2 levels. (This level bonus must be added through the customize option in D&D Beyond because the system is not set up to automate such things.)

Magic resistance provides the Black Opal pseudodragon advantage on saving throws vs spells and magical effects.

Hypnotic Refraction - Bonus Action, 30' 60 degree cone. Wisdom save (DC 8+proficiency+dragon acrobatics) - Those creatures who fail the save are stunned until the end of their next turn.

By twisting in direct sunlight or full daylight, the Black Opal Pseudodragon can press the reflective flecks to just under the glass like scales causing a refractive and prismatic effect causing those who see it to be instantly dazed and stunned unless they are wise enough to divert their gazein time. Creatures immune to charm are not immune to this attack.

This can only be done a number of times a day equal to 1 + the pseudodragons Chr modifier.

As an action you can make 2 melee attacks with your razor sharp claws doing 1d4+ Dex Modifier slashing damage on a hit, also wounding the target who will take an additional 1d4 bleeding damage every turn unless they take an action to bandage or heal the wound.  These bleed effects stack an additional 1d4 for every attack. The maximum bleed effect stack is the level of the Pseudodragon. (I e. A first level dragon can only cause a single bleed effect whereas a 5th level pseudodragon can have a stack of 5 bleeding wounds active at once. Regardless...a single bandage action spent or a single heal will stop all stacked wounds.

melee attack - finesse weapon - 2 attacks -
Hit causes 1d4 + Dex modifier Magical slashing + Bleeding

Bleeding =1d4 slashing damage until the wound is bound

The feared breath weapon of a Black Opal Pseudodragon is your Black Opal Mucous. You can spit a 60' cone of viscous mucous or ooze which when it hits a creature encases it in a quickly hardening beautiful  glittering shell which shrinks as it hardens. Due to your size and capacity, this attack begins very small but increases with experience.

This weapon recharges on a 6 on a d6 die at first.  At 4th level recharges on 5 or 6, at 8th level recharges on 4-6, 12th level recharges on 3-6, 16th level recharges on 2-6, 20th level recharges immediately after use.

When hit with this weapon target must pass a dex save or takes 2d4 necrotic damage and are grappled and restrained as the mucous quickly hardens into a glass like shell increasing target AC by 2 per round up to 4 rounds per level of pseudodragon, shrinking as the liquid quickly evaproates causing 1d4 bludgeoning damage per round until target breaks out by making an athletics check vs their own ac+increased AC caused by hardening shell.

Targets passing their original dex save take half damage and are not restrained.